When you first open up Ninjas Live and then select Recruit from the far right side of the lower task bar. This will open up the Recruit tab for adding Ninjas Live players to your Clan. The main way that you are going to want to do this is with your Ninjas Live Clan Code system. Each player has a Ninjas Live Clan Code that you use to identify yourself. Other people can use your Ninjas Live Clan Code to send you an invitation to their Ninjas Live Clan. Likewise, you make your Ninjas Live Clan Code as available as you can so others can use it to send you invitations.
At the top of the Recruit tab you will see your Ninjas Live Clan Code listed at the top. Below that you will see an Invite Using Clan Code section where you enter the Clan Code you want to send an invite to in the text box. Below that will be in an Invite button that you press once the Clan Code has been entered. Then the invitation will be sent to that Ninjas Live player, who can then accept or deny. Be very liberal with sending out Ninjas Live Clan Code invitations and try to accept any invitations that come in. My Clan Code is M3WQK, so add me to your Ninjas Live Clan.