You got a good deal that worked out well for you, and your friend. He made some money from you. You saved a great bit over buying new.
The Dillon is a progressive press that you have to manual index each station if I am correct. (I still use a single stage.)
Not sure on the RCBS
I concur the suggestion of a manual. Lyman Pistol & Revolver is a great one to start with. Not too long to read the introduction to reloading part. 75 easy to understand pages. That are well illustrated. With good pictures to explain the what you are doing, and why you are doing it. As well as 12 page section on casting lead if you want to get into that. The ABC's is a great read as well. Though having a manual with loads that you will use will be needed as well.
For set up, and using the Dillon youtube is your friend. Also you may end up calling the folks at Dillon for help as well.
Note you will need a dial caliper as well.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.