How thick should the grout be for kitchen tiles 10mm thick?

You're getting mixed up with grout and adhesive. Grout is used after tiling to fill the spaces. Whatever you do spend time working out where to start and don't assume worktops/sills etc are level...they usually aren,t.

Work ot where to start so that you don't end up with fiddling littel strips to cut which will look a pig and work off a straight edge wooden batten. You can comb the adhesive onto the walls with a notched trowel but don't do too much at once or the adhesive will form a light skin and not stick to the tiles. Also the surfaces you are tiling onto need to be clean & dust free... always a good idea to paint walls(especially those that have new plaster) with PVA watered down to about 4 to 1..... But spend a couple of hours if needs be to make sure that all the cuts work out especially round windows, which will be the focal point & what will be most noticed.... more.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.