Range hood installation for non built-in stove
Your stove slides back to the wall. Your venting mounts to the wall - how much over hang of the stove and how much height you have to be able move pans in and out has some factor in this and aesthetics play a part as well - because if you do not have a perfect overhang of the vent - the fan will cause forced air venting.

The Vent you purchased may or may not be suitable for your taste - for example you might not want it to sit back a little but instead cover the entire stove area. Your vent might be for a cook top and not a stove or for a smaller stove.

Many if not most people prefer the unit to cover the burners in their entirety - I will assume your local code does not require a vent for the stove, if it did there might be some local laws that specify what is acceptable or not acceptable.

I would suggest a properly sized vent - typically they are 24 inches deep.