Hi infantmarsupial, welcome to the Linux Mint forums
Thanks for joining the forums! As for what you should be doing next, now that you have installed it, that depends mostly on what you use the computer for or what you want to learn about. Are there some specific things you want to use the computer for? Hobby or family related perhaps, like setting up Skype to talk to your kids with a webcam (if they have left the nest and moved farther away).
Be sure also to check out the Community
website (ideas, tutorials, and hardware and software reviews), and the Cinnamon Spices
website for adding even more themes, applets and extensions to Cinnamon.
You can also chat in real-time with other Linux Mint users. In the Mint Menu, in the Internet section, start the application XChat IRC. You will automatically get connected to #linuxmint-chat for general chat and #linuxmint-help for support with other Linux Mint users.
Have fun with Linux Mint