I run a small Personal training company, and we are open

Hi,

I run a small Personal training company, and we are open from 0700-2200 each day. My problem is that my service providers have different working oppertunities each week. For example:

Service provider 1 (SP1) is able to work monday between 0700-1400, tuesday between 1500-2200 and so forth, but never the same each week. Is it possible for SP1 to go in to the system and add this kind of times?

One more question. Is it possible to use 24-hour clock instead of the am/pm that is used?

Thank you in advance, and sorry for my pore englisch!