@hrvach than you ! going to solder that now ! I didn't notice the * sorry for that.

@hrvach what do you think ? first time soldering. I have 4 more boards, i hope to save one as a spare for another deskhop. so 3 more try

last columns done were B and A right side. B and A left was the one i did first time

Glad I was able to help. As for the soldering, making a few changes would greatly improve your results. You need a bit more flux, hotter soldering iron and you are using way way too much solder. Heat the pad and the pin at the same time, then add a tiny bit of solder and hold for a second to get it to flow. If you add the picos to this, you're very likely to get shorts. Picos go first, then you whip out the iron. Use solder wick to wipe away the existing blobs, place picos on the board and start from opposite corners.

Check this assembly tutorial video: https://www.youtube.com/watch?v=LxI9NYi_oOU and hope that helps you out a bit with assembly.

I have bought like 5 pcb so, i'll try until the last or until i improved significantly without the picos. But i wonder if i'll be able to solder the USB pins because the female usb is already mounted

Here's the second attempt at 375 with a better solder 60/40 (the one in the kit wasn't a good one).
Tried the flux : it's a solid stuff and i am supposed to dip the iron in it from the pic on amazon. Didn't worked well (that's why you don't see the other pins (too ugly to watch lol)

3s iron, 1s solder. I watched your video : you make it look very easy lol !