The simplest understanding of sewing machines is that, for the most part, the function of them has not changed in over a century or so. The basics are still pretty cut and dry, no matter what brand or whether it is electronic or not. Some important things to keep abreast of in basic sewing machine procedure is that tension and stitch width as well as length are important. And threading the upper and lower parts of the sewing machine is necessary to assure that those three entities are doing as they should.
Threading of the machine is at the upper (spindle/spool) and the lower (bobbin) areas. The bobbin thread needs to be wound around the bobbin. This is done by release of the tension wheel found often at the right of the machine. Once released, a spool of thread is wound around the top spindle and threaded to the bobbin in the threader. The bobbin will then thread itself with the push of the foot control. The bobbin will stop winding when it is full. Threading the upper portion of the machine involves looping the thread around the tensions going from down to up through the guides. The guides are small hook-like projections that are placed along the threading path to secure the thread in place. Once the thread is passed through the last thread guide, the needle should be threaded from right to left and pulled under the presser foot. Once the needle has been threaded, turn the tension wheel at the right to bring the bobbin thread onto the thread plate. Once threaded, there are two threads that will make the stitches.
The next concern for the use of a machine is tension and stitch adjustments. There are no real hard and fast rules as to how to do this. Generally, the higher the number for the tension, the tighter the stitch. Tighter stitches can be used for heavy fabrics such as denim, upholstery and leather. Looser stitches can be reserved for lighter and more delicate fabrics such as chiffons, cottons and rayon. The stitch guide is also important. Longer stitches should be used for fabrics that are stretchier and looser woven. Tighter stitches should be used on woven fabrics that do not have a prominent bias.
As with any mechanical piece of equipment, regular cleaning and maintenance are necessary. Before beginning every project, use fabric swatches to test stitch width and tension. The machine should be oiled annually, and the master tension should be adjusted by a professional annually. Most sewing machines will give many good years of service if they are properly maintained.
Sewing is a great hobby. There can be some pride in something that you have crafted yourself. Learning to use the most important tool of the trade will give you many years of enjoyment.