Good Method to Add Wiring For Add-Ons

I’m thinking that the wipers won’t work on accessory, but the blower motor might. I’ll find out tomorrow.
I don’t want anything I’m adding to work on accessory, so I’ll go from there.
Other than test running the engine a couple years ago, this car hasn’t been used since 2008. I hooked up a battery today to start investigating as to what works. Nothing too tricky so far. It’s been sitting out in the garage so long, it’s fun trying out everything!