BuddyBoss Theme and Platform is not yet 100% compatible with a multisite setup. Still, you may try and see if how it works for you.

To make BuddyBoss work with a multisite, you can follow the standard setup of Multisite in WordPress: https://www.wpbeginner.com/wp-tutorials/how-to-install-and-setup-wordpress-multisite-network/.

If you have a 1 site license, make sure to activate your site license on the main site network (network activate). This will allow a new update to take effect within the network which means all subsites that have the BuddyBoss Platform will be updated with the new release even without activation.