First off, I wouldnt bother saving your add-ons, just open them and extract them to your Blockland directory. Making teams can be done with Space Guy's Team Deathmatch mod, found
here. Changing server name and welcome message can be done by knowing how to use the console to change global variables or with IGSO, found
here. If I remember correctly(I don't have Blockland on this computer), announcements are done by saying /announce [message].