Need Advice On How To Evict A Tenant Fast.

I am in the process to buy a property an already have a tenant for it (the former owner). Some of you will say that this is going o be a headache for me, but my guts (as I was told yesterday, that most of the times someone has to trust his guts when it comes to rent a property) tells me that this family will not let me down. But, as everbody knows, we have to be prepared for the worst, so I need some advice on the following: 1. After the tenant defaults on a payment, what is next? 2. When do I send an eviction notice? 3. How fast can I evict the tenant? 4. Do I have to hire an attorney? Thank you.