Buying new properties... The transition to ownership

I am a new investor. I just closed on my first two rentals in Baltimore City. Two adjacent Duplexes.

I am having difficulty with getting available time with each currently occupying tenant to change locks, get leases signed and everything else.

The previous property manager was terrible and had barely any documentation. One lease is missing and a security deposit.

How do I reasonably work with my availability vs. tenant availability? (This isn't my full time work yet.)

How do I do this transition well? What are some lessons learned with this transition "you who have gone before me" would pass on? Any newbee advice would be great. I'm sure there's a ton I'm not considering.

Method of payment for rent thoughts? How many should I offer? Using Cozy and mail right now.

Lease help please. Using Master Lease on BP now.

Thank you,

Don