After you mark the line (about 2 thirds of a tile up) you attach a batten to each wall to stand the tiles on, this prevents wet tiles slipping down the wall. Many tilers use alloy angle for this with pre drilled holes at the inner end then spaces 600 mm apart to meet frames.
Use spacers between the tiles to ensure no slippage also.
That Aus Standard requires floor tiles to be under vertical tiles, this also applies to hobs.
Hope this helps.
Good luck.