Hi, We have a Solac siempre crema espresso machine that is pretty old. Anyone know how to use it?

Expresso machines are pretty standard. They create steam, which is then forced through the coffee.
Do a "dry run" with just water in the machine (making a cup of hot water…) and you will determine how to use the various controls. Then, all you have to do is put some coffee in the right lpace, and away you go.