Today I collected some tools and materials I ordered on Saturday. I've got an A4 paper-trimmer for cutting margins of the templates. OK, the templates are only an excuse, I always wanted to have one. The one I got is: cheap (10 €) not too robust although it has some nice features. Not only it cuts paper in two but it can also make traces for folding, do "wavy" cuts and perforation. I also got a cutting mat (6 €). I wanted a branded blue one but just before hitting "BUY" I realised it has got inch based grid (no I won't write here: "oh, don't get me wrong there is nothing bad in inches but…", honestly I think inches are weird and require lots of nasty Kowalsky's constants when you do some physics). So I found this one, it is cheaper and bigger. When I buy things on Allegro (eBay isn't very popular in Poland) I always check what other items a vendor's got for sale. And next to the mat there was a Velcro tape, 50 ¢ per two metres of tape (or one metre of complementary tapes). That is ten times cheaper than a self adhesive velcro in a hobby shop. Conclusion: if you want something cheap go to a haberdasher.
Material-wise I got some pine slats and a sheet (210x410x1,5 mm) of (birch?) plywood. I really wanted to try posicle sticks and they would probably be cheaper per square unit. If only they were available.
In the evening I took the templates I've printed, cut them out and stuck them together. To cut the foam I need to get a block of wood from the carpenter and cut it at 45°. I am afraid I can't hold the knife straight enough to cut wings the way Mikey recomments.