Welcome to the board! I'm sure you'll find your way around with all this good advice.
Bobbin tension is a tricky thing. Many people will NEVER touch that little screw on the bobbin case. But it's not so hard to find out if there is a problem there.
Take your bobbin case out with a bobbin of thread in it. hold it up by the thread. With a little jerk, the bobbin should lower a little and then stop. If it won't lower at all with a small jerk, then the screw is too tight. Loosen it just a little, not an eighth of a turn. If it lowers and won't stop, the screw if too loose. Tighten it just a little and try again. Sometimes the tiniest amount of turning that screw will make a big difference. Keep working until you can hang onto the thread, give a little jerk and the bobbin lowers a few inches and stops. Then it's perfect.