I have completed my shower floor/pan with the final layer of deck mud. I am ready to lay down my 2x2 porcelen tiles and did not know if I needed to do anything more to the concrete base before applying the tile. I have a fresh clean smooth new concrete to wor with. Is that enough? What thenset do I use? Any feedback would be greatly appreciated.

I normally use a 1/4x1/4x1/4 square notched trowel for that. Use a good quality modified thinset. Dry-lay the floor first and get all your cuts made before you mix up thinset. Then pull up the tile on the back half of the shower, leaving the front half as a guide to lay against. Once you get it in place, do the same with the front half.

If you try to do it all at once, you most likely will not get it to lay exactly the same way and your cuts will be off a little.

Using a grout float, press the tile into the thinset after each section is done. This ensures good contact between tile and thinset, and will help level the tile a bit.