Using a sewing machine is just practice. Get some scrap material at home and draw some lines with pencil. Then practice sewing over them. Practice pinning some material together, then tack alonbg the line you want to sew and then sew it (just 1mm or so inside the tacking so it is easier to get out).
Learn how to thread up your machine so it is not a barrier for you. Then learn what every knob and button does and try a few to see how they turn out. Try changing the tension and see what happens. Just try things. That is the only way to find out. You may break a needle or two, but they are easy to replace.
Just, whatever you do, don't sew your finger! OUCH!
Have fun. Textiles is a great subject. I took it to Year 10 when I was at school and had a ball. The trick to good textiles is precision.