What do you mean by "free spin"? Is the engine turning too when you turn the key to start? If yes, you have some sort of other problem. If no...the starter turns but the engine doesn't that means the starter drive is shot or (unlikely) a bad flywheel that has worn teeth.

Never changed a starter myself but it's definitely a job underneath. It's down below and behind the oil filter. Probably best to put the Sportage on ramps to get enough room to work on it.

1998 Sportage - Gone.
2004 Honda Civic Coupe.
2007 Suzuki Grand Vitara - She got it.