Team playerTeam = TeamManager.getInstance().getTeam(offlinePlayer);

Team t = ... ;
List<TeamMember> membersAndOwner = t.getMembersAndOwner(); // get members and owner
List<TeamMember> members = t.getMembers(); // get members

// Team creation event
@EventHandler
public void onTeamCreate(TeamCreateEvent event) {
    OfflinePlayer owner = event.getOwner(); // Get the team owner
    ...
}

// Owner changing event
@EventHandler
public void onOwnerSwitch(OwnerSwitchEvent event) {
    TeamMember lastOwner = event.getLastOwner(); // Get the last owner
    TeamMember newOwner = event.getNewOwner(); // Get the new owner
    ...
}

// Team deletion event
@EventHandler
public void onTeamDelete(TeamDeleteEvent event) {
    Team team = event.getTeam(); // Get the deleted team
     ...
}

// Team join event
@EventHandler
public void onTeamJoin(TeamJoinEvent event) {
    Team team = event.getTeam(); // Get the team
     OfflinePlayer player = event.getPlayer(); // Get the player joining the team
     ...
}

// Team leave event
@EventHandler
public void onTeamLeave(TeamLeaveEvent event) {
    TeamMember teamMember = event.getTeamMember(); // Get the leaving member
    ...
}