I have a 1975 Chevy Laguna I don't know anything about cars but don't wanna miss this opportunity to restore my childhood car.. so my dad mentioned the car did run nothing wrong just stopped using it it a been sitting for about 15yrs or so.. what should I do first...

thanks I'll go from this video 👍

one more question sorry.. it's been leaking oil is it wise to add oil before I start it up including trans fluid and water or just do what the video says to see if it starts ??