How do I implement multiple signal handlers using sigaction?

Question

I'm trying to figure out how to use signal handlers in C via sigaction and it's desperately confusing. signal() is extremely straightforward, and works, but apparently Linux dictates it can't handle asynchronous processes, so I have to use sigaction. The confusing bit for me is how in signal(), one can very easily refer to various signal handler functions and it will automatically do the handling. I'm extremely confused on how this works with sigaction(). Do I simply add a secong sigaction struct?

Thanks in advance