Noob: Clivia removed, now what?

Hi all I had a forest of clivias that I removed after buying a house. Now I want to keep that area clean, prevent weeds, flatten it out a bit and mulch.

As you can see there’s lots of roots leftover. Do I need to get rid of these somehow?

I saw a tool online called a cultivator, seems good for breaking soil up so I can even it out and then putting mulch over?

How does one learn all about gardening?