Trying to house hack - tenants?

[Matthew Weisheit]

First time investor or home owner for that matter. 24 years old single doing this thing by myself new to everything. Looking to house hack. Got pre approved and trying to take down a property working with an agent. There are a lot of properties on the market but a majority of them are fully rented or partially rented. If there is a property (triplex for example) that is fully rented can I refuse to renew the lease for a tenant and plant myself in the property while also adhering to regulation and law and if so - how do I determine which tenant to not renew the lease or am I going to have to not renew all of their leases? And secondly, if a property is partially rented and I can insert myself into the property do  I find new tenants or keep the tenants (assuming I can not renew the lease). 

Regards,

Matt