I haven't changed one either - but I'd guess your biggest difficulty will be finding the correct replacement carpet.
There are places which make carpet sets for "classic" cars, but I don't think the Panda qualifies, yet.... also their products are generally cut from flat carpet and have sewn joins to create the curves around transmission tunnels, wheel arches and the like, whereas an original Panda carpet is a one piece molded lump.
Short term fix might be glueing a cut to shape large footwell mat over the footwell (and holes), as opposed to trying to find the correct fitting carpet.
Replacing a whole carpet will involve removing both front seats ( not difficult* ) and loosening, or removing, the kick step trim... as far as I can see it just has bent metal tabs in the other odd places# - unless anyone else knows better, of course
Regards
John H
* undo the two bolts into the floor where the supporting tube is clamped - immediately below the font edge of the seat.
slide the whole seat backwards off its runners - you may have to bend back the tabs inside the runners which stop the seat sliding back too far in normal use.
Clean the excess grease off the seats and runners so you don't mess up the new carpet on refitting [V]
# may have to undo the bottom seat belt mounting bolt - can't remember, and it's too rainy here ATM :I