How do you lock parts in Fusion 360?

How do you lock a component in place in Fusion 360?

Right click on the component, and select the option to ground. Its the second option from the top. Or as ZimbuRex said, you can also use a joint. Either use a rigid joint from the component to the top level origin.

What is the difference between a body and a component in Fusion 360?

Components have their own origin planes, whereas bodies do not. We established earlier that components are parts in Fusion 360 that can have motion relationships with one and another. This is made possible due to them having their own origin planes.