Prefab shower drain installation - slab on grade

[Rutherfordman]

This is probably not rocket science but could someone walk me thru how to install the drain on my new prefab shower base. I have a 2" PVC pipe in a box out (slab on grade)for the shower with the trap below slab. I need to buy the correct drain from one of the big two home supply stores. Which one do I get? Also how do you get everthing water tight and adjusted properly when you can't get to anything from below or the side?

[hj]

Get a drain with a rubber gasket seal, so you can install the base OVER the pipe, and then push the seal in around the pipe.