When you are just learning to sew there seems to be so much to learn at once. That is one reason why it is good to keep your machine handbook nearby. You also have to take time to practice each skill as it comes along. Threading your machine is a great place to start. Read the instructions carefully, thread yourmachine, try a few stitches to see if you did it right, unthread your machine and start over. After you do this 3 or 4 times it becomes easier and more natural.
But I know that many of you may have weeks or months between sewing sessions and it can be hard to re-learn this every time you sit down to sew. When I learned to sew on different kinds of industrial sewing machines learning to thread each one was a big challenge. Even now it can be very time consuming to get them threaded correctly, especially my serger.
Here is a trick I learned to save time and frustration when I want to change thread color: tie the new thread to the old and pull it through.
Even with a portable machine you can keep your machine threaded when you put it away. Just cut the thread close to the spool and leave the length of thread in the machine. The next time you start to sew or whenever you want to change thread colors, tie a knot between the old the thread and the new, pull the old thread completely through the machine. Many times you can pull it all the way through the needle.
Now your machine is threaded with a new spool or new color. You are ready to start a project or try practice stitches on real fabric. Have fun.