Comprehensive Car Retune & Maint. Checklist

Hey there mechanics! I'm someone who's never been particuarly car savvy, and would like to change that. I have a Hyundai Elantra that's been sitting in my driveway for over a year with a starter and/or battery issue (I think) and I would like to get it restored/tuned back up to running condition, and fix whatever is wrong with it.

Considering how long it's been sitting, where exactly should I start? Is there some sort of checklist or guide to something like this?

Any help is appreciated here; thank you!