Question about interlock

Hi!

First time offender in PA and I was accepted into ARD. Trying to navigate the interlock process.
My suspension begins for 60 days on 10/06. However, I need to get the interlock due to driving to work with an hour round trip, uber is too expensive and I can’t rely on others constantly to drive me places when I need. So I have the following questions if anyone here can help or provide their own experiences!

1. Do I go through PennDOT and get approved for interlock then buy it? Or do I buy the interlock first?
2. Do I only need to keep the interlock for 60 days? That’s how long my suspension is. I’ve read it can be a year.
3. Does approval for a restricted license take awhile?

Thank you in advance!!