Most excellent. and welcome to hobbyist car fixing. You can learn lots on these forums. My number one advice is to find a GOOD INDIE PARTS STORE. If the store employees look like they have never heard of a PCV valve, or are experts at selling Air Fresheners, and pushing the counter product of the day... this is NOT your part store.
My part store rocks. There's several parts veterans there... and they sell to many regional repair shops. That's the first clue you are onto something. 2nd clue.. They have super good filters in stock. Look for brands like Hastings, Wix, and Purolator. When you need a part, do they have to order pretty much anything, or can they have it later today, or it's in the back..... If they seem to have nothing in stock for a car as common as a Focus, this is NOT your part store. Do they specialize in shiny lights to put under your dash board? this is NOT a parts store... it's a BS retail operation.
A good part store has real stock, smart people that get you the RIGHT part, and the prices are totally fair. There's no "super protection warranty" for an extra 20$.. none of that crap. Just parts and smart people.
My car part stores are "Car Parts Warehouse" (carpartsplus) and my most favorite. Fisher Federated (Federated Auto Parts). The big losers are the shamrock guys, and the big orange zone. the Red place with the checkered flag isn't on a hate list.. so they get me by in a pinch.