The NEC (US) would want you to consider the service as a "detached structure".
You would run 4 conductors to a 60A breaker, N and ground.
Generally size for a 3% voltage drop at 80% load.
There's wierdness for continuous and non-continuous, but I won't go there.
If your going to run an air-compressor, you may have to worry about that too.
there are two types of panels:
a) main breaker and main lug
b) The main lug doesn't have a service disconnect. A main breaker panel is required when, i think, the circuits exceed 6,
The NEC can be read online for free. No printing.
The breaker can be rated for 200A if you want too. Short circuit protection is at the main panel. i.e. 60A 240V. Never load a breaker for a "continuous load" more than 80%.
You have to buy a ground bar conversion kit for a sub-panel.
In the sub-panel you want to keep the neutrals and grounds separate.
There should also be a way to remove the neutral/ground bond (i.e. remove a screw)
Since this is a sub-panel in a detached structure, you need a ground rod as well. You still keep the grounds and neutrals separated.
Where your located, helps.
"/