For Skype for Business Online organizations, you can use the Remote PowerShell in Office 365 to enable your Skype for Business users to use the Skype for Business client or the Skype for Business (Lync) client user interface. The default setting is for users to use the Skype for Business client user interface.
Yes you do - all of it, but under most circumstances, not until after you graduate college (or leave school for other reasons). Under normal circumstances when you graduate or drop below a certain # of units of attendance, you will be expected to begin paying back your student loan 6 months later. For subsidized student loans, this is when the interest will start accruing as well.
Other loans, such as the Federal Direct PLUS loan, have no grace period. If you are a recipient of such a loan, you must begin paying it back on the day that the last part of the loan is disbursed to you. However, it may be in your interests to start making payments on your loan even during the grace period.