Hi Lexi,
Here is some links which explains in easy way,
Response groups:
https://blogs.msdn.microsoft.com/ahgyger/2010/10/21/creating-a-response-group-1-enabling-an-ad-user-to-be-a-lync-user-with-enterprise-voice-enabled/
(There are other parts also in this series)
Skype for business control panel:
Technet gave perfect links with explanation,
https://technet.microsoft.com/en-us/library/gg520943(v=ocs.14).aspx
- Muralidharan. Please mark as answer/useful if my contribution helps you.