How to calibrate your printer from start to end

Well, I’m struggling to make this printer to work reasonably well. I’m quite noob at 3D printing and printers and I’ve been trying to follow some tutorials from 3D PrintBeginner and not only but I still couldn’t make the printer to give good results.

To start, I’m just looking for a guide that tells me which procedures to take and in which order.
For instance, probably the first step is to level the bed with bubble level and then adjust with the 4 screws of the bed. But what follows? Flow ratio calibration? Temperature? Retraction? What to do next? Is there a order of procedures to take?