How do I prevent my weapon abilities from hurting my friends?

Simply Swords utilises Vanilla Minecraft Teams. To ensure you do not damage your friends, you will need ot join the same team using the in-game commands below:

/team add teamname
/team join teamname

Alternatively, you can also use Open Parties and Claims to manage friendly fire in the same way by joining a party.

How do I allow my weapon abilities to buff/heal my friends?

See the commands above ^

Note:

Disabling PvP on the server will have the same effect.