Ok...
I got your back on this
""IF "" that weep ring in the 2nd image is not broken
AND
"""IF"" all the holes in the drain body in the 1st picture are not screwed up and useable
THEN. this will be a cake walk.
First, use a wire brush or a wire wheel on a grinder and clean everything up
oile the threaded holes and verify they accept a bolt
you want
Shower Pan Liners order from here
Measure the shower from wall to wall
then add 16'' for the sides
add 16'' for the front/back
in other words if your shower is a 48'' x 48'' shower
you need 5'4' x 5'4'' drain pan material
lay the material down in the shower. CENTER IT
place the weep ring over the pan on the drain. punch a small whole for the bolts
bolt the weep ring to the flange. YES the material is covering the dran hole
smooth the pan out. fold it up the walls. put a nail at 6'' off the floor NO LOWER
on the corners. fold the corner so that if water drips it will drip into the pan