While glass isn't a bad idea (you can clean & re-stamp)
Any flat smooth flat clean surface is great to practice on.
I think one of the two, is the best way for you here.
Paper is a cheap method of "proofing" the print quality of a newly finished stamp, screen, plate, type block, etc.
Normal for beginning production runs, its use is a "must".
Unless you are printing on paper its end results will be quit different on a different surface. If it must be paper, stick to high gloss paper for the practice.
Landing even, with little to no "*ink press out" is the goal. (*oozing out the sides)
But
By hand, on small stamps, better results can be achieved by some, with a slight "roll"
I prefer landing the top edge 1st, resting & applying lightest pressure there. As I let the lower portion drop, and contact, I roll towards myself and lift, almost simultaneously. This causes press out to move away from the upper edges of the type, leaving a sharper line on top, where the eyes tend to look to form an opinion on which letter/number it is they see.
Place something on each side and brace your wrists.
Use two hands
Set up a guide rail to keep it straight.
Mark the center of the type along the side of the stamp, to align with a center mark on the piece to be stamped (registration marks) (mark on tape then remove tape later)