If you never soldered before, please check out an online tutorial or ask somebody to teach you. It’s not a hard skill to learn!
Some general tips:
- Use more flux!
- Don’t skip on cleaning the circuit board after soldering. The flux might be corrosive and/or conductive. Isopropyl alcohol would do the trick.
Here’s a quick guide by Mitch Altman and Andie Nordgren (taken from PEN wiki):