Read, reread, and reread the manual. Figure out one thing at a time. Maybe start with winding a bobbin. After you have almost memorized that section in the manual, do it double checking yourself ever step of the way. Then wind so many bobbins that you are comfortable with that. Do the same thing with threading the bobbin. Take the bobbin out, rethread, take it out, rethread... there is no hurry at this point. When you are comfortable with that step move on to threading the upper thread of the machine. The manual is your friend!