That last point is super important - basic approach is to make a small glob/reservoir of glue on some scrap paper, and keep a box of toothpicks handy to use as applicators to transfer the glue onto the the tabs. When the dried glue builds up on a toothpick end (making it bulky/less precise) just toss it and use a new one. If your goal is to build clean, tidy models with no trace glue or smudging, this is the way :)
The only other glue I occasionally use, and only then very sparingly, is some kind of cyanoacrylate adhesive. Typically "Krazy Glue", in the tubes with the fine/precision tips, though I'm sure any brand will do. I reserve this for bonding together joints of a model that bear a lot of weight (think like, long, freestanding structures attached to the core of the model at a single point; see [0] for an example with structures like this!)
Edit to add: Wow, that Deep Striker model is incredible!
I like hot glue for this type of work because it gives you a _little_ bit of leeway to make mistakes while it's still warm, so you can slide the pieces around to get them just so. Then it cools and hardens quickly so you don't have to wait a long time before moving on to the next piece.
https://media.wizards.com/2020/dnd/dragon/31/DRA31_DRA86.pdf
Loads of sanding and spray painting, in-all I think it took me about 70 hours, but we wore the helmets loads for festivals and parties.
I no longer have the file sadly, but got it from a paper craft forum - where people posted them. Happy to share pics if of interest.
I basically got a 2 sheets of MDF to the size I wanted (roughly the size of a baking tray for the oven, as I had to heat the plastic in my home oven) then drilled a hole every couple of cm in one of them, then made them into a shallow box - sealing all the places the wood connected with bathroom sealant on the inside and duct tape on the outside. I made a hole in one of the 'side' pieces that would fit my vacuum cleaner hose, and then added more duct tape to seal.
Then I made two wooden frames as big as the largest baking tray for my oven, then cut some heatable plastic to size, and clamped them in the two frames and put them in the oven.
This part had loads of trial and error - ie how long the plastic needed heating, how long to run the vacuum cleaner, how to make sure the plastic didn't end up behind the thing you were forming, how to make sure the think you were forming didn't deform while under pressure.
Email in bio if you want pics or more info.
> I recommend printing these toys on HEAVY CARD STOCK.