Originally Posted by Homebrew01

"Freewheel" and "cassette" are 2 different things and not compatible.
The link shows a "flip flop" hub because can have a freewheel on one side and fixed cog on the other.
Probably simpler and cheaper to buy wheels, unless you really want custom and can build yourself or pay someone to.
If your old rims are steel, they may be 27", not 700c that is common now. If you switch to 700c, first verify your brakes will reach the rim.

The listing doesn't specify hub width. You bike is probably 120 or 126 mm. You can use a hub that is a few mm different, but i wouldn't put a 135 hub in a 120 frame.