This is in the wrong category, but
You must use a permissions management plugin, such as PermissionsEx or LuckPerms.
If you're using PermissionsEx, use
/pex group (name) add permission.node
to add a permission to the group.
If you're using LuckPerms, use
/lp group (name) permission set permission.node true
to add a permission to the group.
If you need anymore help just quote me