I cant…rember how…

BuddyPress is … tricky.

https://codex.buddypress.org/getting-started/install-buddypress-on-a-secondary-blog/

thanks. what about other plugins. what if I want some plugin to be only for the second, third or forth site and not on any other site?

BuddyPress is network wide.

Othe rplguisn:

– activate it on whatever site you want. Do not network activate it.

– if you want to *hide* it from other sites, that;s different.

https://www.ads-software.com/extend/plugins/plugins-enabler/
https://www.ads-software.com/extend/plugins/exclude-plugins/
https://www.ads-software.com/extend/plugins/restrict-multisite-plugins/

Try this :

https://www.ads-software.com/extend/plugins/plugin-manager/

Different question, and you DO NOT do this with BuddyPress.

BuddyPress is, generally, for your NETWORK, not per-site. There is a new plugin to let you have multiple BP installs per Network on a Multi-Network site

https://wpmututorials.com/news/new-features/multiple-buddypress-social-networks/

But if we’re just talking normal plugins..

PLUGIN MANAGMENT
* https://www.ads-software.com/extend/plugins/exclude-plugins/
* https://www.ads-software.com/extend/plugins/restrict-multisite-plugins/
* https://www.ads-software.com/extend/plugins/plugins-enabler/