You are in Luck Sir...
The bottom is a 4X3" p.v.c. closet/toilet flange that can slip in 3" p.v.c.D.W.V. Drain, Waste, Venting Schedule 40 Pipe...
Then a 3x1/1/2" p.v.c. d.w.v. Tee (ASSUMING YOU USE 3" PIPE...
a'PC.OF 3" P.V.C. D.W.V. PIPE (SOLID OR FOAMCORE)OR SOME CALL IT CELLCORE ...
1 1/2" x1" P.V.C. Bushing used as a reducer...
1" p.v.c.pressure tee where it splits
2-1" reguler 90 degree elbows
2-1" caps
1-4oz. can of p.v.c. glue/cement if you glue it...
1" p.v.c. plastic pipe..
You can buy the pipe in 5' sections now at Lowes...
You also need a board and about 4 to 6 3/4"wood screws to mount to the board...
Hope it helps ya...God Bless , Keefer's <><