I've often likened an automobile to a computer for some people, the CPU being its engine, the RAM how fast it could get there and HDD how much it could carry, or some such BS, but it isn't really difficult to liken a computer to a vehicle.
Surely you've twisted wrenches somewhere at some time, that's about as simple as lefty loosy and righty tighty
If you add up the cost of a repair manual and a set of tools and subtract it from what they've charged you this far, think about how many parts you could have put on it yourself
One example, and I rarely turn to a shop, even being the novice I am, but mine wouldn't pass emissions, and to have it tested was going to cost me $250, simply to test it(and possibly give me a clue). After studying the emissions system I found there were 5 basic senders it could be, each one costing appx $50.
I took my best guess and replaced that one, took it back to emissions, and it passed, the very first one!