How to replace the glass cooktop on a GE Spectra range

If you were referring to replacing the "cook Top"

it's pretty simple....

turn off power

open oven door

remove the 3 or 4 screws that hold the top down in the front

raise top up, use a board or something to securely hold the top up
as you will need 2 hands to remove burner assemblies.

burners should be mounted on plates, remove the entire plate
with burners attached  carefully laying them down.

repeat with rear burner assembly

now the top is ready to remove.

Normally it just sits on the hinges in the back,
there shouldn't be any screws holding it on
but you may have to look at the hinge closely
to see how the top needs to be manipulated to
remove it.