Sewing on an antique hand crank sewing machine is not very different from sewing on a treadle sewing machine (see posts below). Really the only difference is that you will only have one hand to guide the fabric that you are sewing. This may sound difficult, but it is not.
With your right hand on the crank you always turn the crank away from you. Your left hand gently guides the fabric from the front. It is very easy.
The only difficulty you may run into is if you are trying to sew something that has gotten large. In that case you will need to make sure you have your sewing machine on a table large enough to support your entire piece.
It’s as simple as that! 🙂