We did a test run for the kitchen with regard to laying out the tile (offset grout lines or lined up grout lines) I just used a loft board as we had some spare. We laid the tiles down on the board, and grouted them. Just a few rows to get a feel for it. The tiles were the ones with tiny imperfections which we wouldn't have used for the kitchen anyway.
You can buy ready mixed both adhesive and grout combined. Good for a beginner.
You need to think about where the tiling starts and finishes and you need to think and plan it. Plus what are you doing with the edges?
Think about the middle of the range cooker and are you staggering tiles or stacking them? I am a bit obsessed with symmetry so my tiling is all the way round the kitchen but we made sure we framed out the window so either side is the same.
I have tiled a lot of things, including lots of different sized tiles too. Dry run it first before you commit. And a handy tip for you, put adhesive on the back of the tile rather than the wall, that way you don't have it squishing through the grout lines. Clean up immediately.
Use a grout sponge - not any old sponge. We have a small spirit level that we use to sit on the tiles to make sure we are still straight.
Here is my kitchen, we tiled it a few years ago.