The piece in the drain is screwed into the drain under the tub It is usually corroded and is not going to unscrew. You can use a sawsall or jig saw to cut the drain in 3 or 4 places around the opening and peel the piece out. You can also disconnect the drain under the tub and just leave it on the tub. There should be access to the back side of the tub. Usually a panel or door in the back of a closet that is in the room beside the bath. If there is no access, you will need to make one so that you can connect the drain to the new tub.
You step on the plug in the drain? The plug is part of the trim ring and screws into the drain. It seals the drain to the bottom of the tub. You can remove it and replace the drain completely, but you can't take out the plug.
15-16 inches from back wall. 8-10 inches from side wall tub drain is on. Measurements are to center of tub drain hole. Measurements are close, not exact, and are for a standard tub.
A right-hand drain applies usually to bath-tubs and means the drain is on YOUR RIGHT when you are standing in front of the tub.
a bath in a tub
One the end of the tub above the drain there is a plate. It may be where you close the drain off or it may just be a cover plate. It is open on the bottom edge and goes into the drain so that the tub cannot overflow.
You can access the tub drain by cutting through the ceiling below, or cutting through the side wall backing up to the tub.
Carcengenic fruit flies
yes
tub baths are when you take a bath inside the stone in a tub
You screw the drain piece out of the tub. Not easy,as there are many threads on it. You can get a special tool for it in plumbing stores.
Yes I can but it is easier if I have a helper to hold the tub shoe in place unless it is a standing waste then I do it alone
That depends on the volume/size of the tub in question. A "tub" could be a butter tub, a mash tub a bath-tub etc.