Hi there! Name’s Jack.
Last time I did a WWII model was in the early 90s, lol. Just got three. Had no idea the Russian one was 1/100 and how small that really is, or that it was from Russia 
Which one should I do first? I’m old enough to be tedious now, what should I do to get started in terms of prep and gear? I’ve got some stuff already but probably need lots more. Let me know if I should re-post in another category. Nice to meet you!
Welcome to the Hotel Kitmaker Jack, you can check out any time you like but….
You join a welcome line of recent newbies reviving their hobby who’ve asked similar advice, so you might want to trawl some recent threads in the AFV sections. I’m also sure better advisors than I will help you out here too. I’d just somewhat impishly suggest that the Zvezda armoured car might not be a lost cause – if you get into dioramas, it could be right at the back to give the impression of distance 
Both of those Tamiya kits were already old back in the 90s, so whatever you used back then would apply to them now.
They will make good and relatively cheap subjects to test your level of ability and then start trying new things. Just build them in the normal fashion, and then the painting and weathering will be where the new stuff that came along since your last kit will become relevant. You will find the subject of paint alone will occupy much of your time attempting to select a brand (I recommend AK Real Colors but other people’s MMV).
Welcome back to this wonderful hobby, Jack, and good luck!
Cheers
Peter 
Welcome back @knavejack and hope you enjoy it …As your not a complete first timer, you have an idea of the basics so thats a start … I would do either of the tamiya kits as the start kit and build as normal with no thrills or spills and see how you get on with it. When you do start the builds, begin a new thread in the Armour section, and do progress updates and images, and there will be a mass of people able to lend advise or guidance on painting or finishing etc should you wish it … and sometimes even when you dont want it lol … … For what its worth my go to paints are Tamiya and AK real colour range which I lean towards now… look forward to seeing the builds as they take shape.
Welcome (back) Jack, nice to have you here.
I would recommend the Panzer IV, which will be easier to paint than an open-top vehicle.
Welcome back- have fun!
Tamiya extra thin cement is currently popular. Tamiya acrylic paint used with their yellow capped lacquer thinner is also very good for spray painting but not brushing. Life color is another good paint choice. You will find (involving paint) that one person’s salvation is another’s poison. There are currently many YouTube videos out there on how to do most everything. Big changes involve the kits themselves. The 250 part kit was popular in the 90’s however, welcome to the 1200 part era. multiple part indy track and complete interiors await ahead. Kit prices can be expected some where between 60 and 80 dollars before shipping. Scalehobbiest is a good starting point for online shopping. Make sure your seat belt is securely fastened, keep your hands and feet inside the car and enjoy your ride.
Welcome to the forum and back to the hobby.
I’d start with the Tamiya Pz IV for the reasons mentioned above.
Welcome aboard Jack. 
Wow, thanks for the kind greetings everyone! 
It looks like Tamiya thin cement is first on my list along with paints. Maybe one of those green matt/grid things and build a carboard back drop/enclosure thing?
This is what I currently have. I haven’t used the air brush thing ever just carried it around with me for an unknown number of years. Pz.Kpfw. IV it is!
Use the side cutters 50 times more often than the knife.
Get sanding sticks from the cosmetics department or glue fine sandpaper to wooden sticks.
These methods cut back on the number of times I sliced my fingers and saved a lot
of money from reduced purchases of nr 11 blades.
Oh, Robin reminds me of something:
For many things like sanding sticks, sponges, some brushes, and other odds and ends at a better price than the hobby version, check out beauty supply shops or the cosmetics section of a department store.
I primer my tank kits with spray primer and paint my automobile kits with spray cans as well. Same stuff you’d paint a bike or a mailbox with. Save your hobby shop money for kits and specialized tools/supplies and buy the mainstream version of everything else. Once you learn the airbrush and understand thinning of various paint mediums you will realize there are a lot more things than the paints in the model section that you can spray through it.
Some modeler told a story (possibly way back when rec.models.scale still existed).
He had gone to the cosmetics department and loaded a basket full of supplies (cosmetics powder is essentially pigments that can be used for dust and weathering. I wonder if mascara could be used for something else than eyelashes?, Lots of cool colours in the nail polish aisle et.c).
When he was standing in line to check-out and pay he got strange looks from the ladies (customers and staff: “Eww a gay, cross-dresser or transsexual, Eww, they shouldn’t be allowed in shops where decent Americans shop”) so he felt that he needed to say that all the stuff he had purchased was for his models.
Suddenly the other customers were very interested in him:
“Ohhh! A model agent or maybe photographer! How interesting! I wonder if I could get a job modeling for Vogue or something. I’ll take the opportunity and introduce myself …”
The models you have shown look like a great start.
The next most important thing is rush about buying references and aftermarket until you about doubled the retail of the kit (preferably 3 or 4 times…) and then to shelve the models because you don’t think you can do them justice.
This becomes your ‘stash’.
Then buy more kits. repeat above steps. It’s okay to occasionally build a kit, or even sell one or two on at considerably less than you originally paid. Beginners should look at purchasing at least five stashers to each attempt to actually build. Gradually increase the ratio until domestic harmony is threatened.
open all kits. smell the plastic. dream about complicated conversions. test fit a few bits. lose the instructions. put it back in the stash.
order another kit.
