We're trying to organize all of our customer contact information. 

B2B customer has account X with contact John Doe

We have a contact named Jane Doe that we want to associate to this account X, but within the account we can't do that. There's no + button next to contact but there is with just about every other module on the left side.

How can I add this contact to this account?

Also, what is the difference and / or purpose of having both account and company fields?

Thanks!