how do I add a new printer?

Please follow instructions given in these articles.

https://support.apple.com/guide/mac-help/add-a-printer-mh14004/mac

https://support.apple.com/en-us/HT201900

In addition to this follow instructions given by your printer manufacturer.

There are different processes with each printer and different manufacturers have different ways. If the printer supports AirPrint then the process is very easy. You can start by going to System Preferences > Printers & Scanners. At the bottom of the white window where there is the list of printers, you'll see a "+". If you click on that, you'll be able to follow the prompts to get it installed. If it does not support AirPrint, then you are probably going to want to go to the Support Page on the printer's manufacturer page so you can the help needed or find the software needed to install on the MacBook Pro to get the printer installed and added.