1)
Read this sticky2) The + means that you are voiced in the channel. This is a setting that the channel ops control and we have no say or control as to who or when it is or isn't issued.
3) Registering your nick is usually done with a command like /msg nickserv register <password> <e-mail address>
3a) <password> may be case sensitive
3b) <e-mail address> should be a valid address, as many systems send out an e-mail containing a confirmation code, which you then have to send to nickserv.
4) The best place to get help for registering your nick, is the network's help channel. Usually something like #help