Some aspects of large-format wall-tiling are covered here:
Sal DiBlasi has some informative vids:
www.youtube.com/c/SalDiBlasi/videos
As others have already said, use powdered adhesive (also note that
ready-mixed adhesive is downright unsuitable for large-format tiles as there is a risk it may never cure fully). Be warned that many powdered adhesives go off quickly, so it's best not to mix huge batches, and it's best to clean your whisk immediately after mixing, just as you would with skim. BAL and Mapei are both good quality.
Although it's great for plastering, NEVER use PVA to prime surfaces for tiling purposes!
Spread a tight thin film of (bagged powder) tile adhesive on the back of the tile, and a combed coat applied to the wall. Note that it is good practice to comb the adhesive entirely in one direction (I mean for the final comb-stroke) which means the lines travel across the
shortest dimension of the tile.
For example, if you were applying a 600 wide x 300 high tile to the wall, then all your tile adhesive would be applied to the wall so that the combed lines run down the wall. The reason for this is so that you minimise the risk of trapped air pockets in the adhesive when you squish the tile onto the wall, and also so that shorter lines of combed peaks offer less resistance as you squish the tile sideways, back&forth.
