I suggest you practice your soldering skills until you can make a good job of it. There are plenty of online videos and tutorials to help you and there are kits out there on which to practice. Also get yourself a cheap multimeter so you can test for contunuity and short circuits. You don’t need a fancy one, but if it has a beeper to indicate continuity that helps. There are also plenty of tutorials to learn how to use a multimeter, e.g. https://wiki.restarters.net/How_to_use_a_multimeter