Buy very thin solder wire. I was struggling until I realized that the wire was too thick. I got thinner wire and everything went smooth.
But cheap practice board for soldered (few USD) and practice first (desolder and solder again after you finish).
If your iron don’t have temperature control, but something that has it. I paid around 10usd for mine.
Go with switches first, do controller later, it’s slightly more difficult
I bought iron specifically to solder keyboard. I practiced for like 6 hours with some cheap practice kit before starting keyboard.