mysql cluster set up as a beginer (no replies)

It may be a very fundamental question. i have been searching for setting a mysql cluster. I have downloaded mysql cluster auto installer for windows. I am following the steps provided in the quick start guide provided in that web site. I have the following questions regarding this procedure:

1) In the hosts list, if i mention 3 hosts say 192.168.9.10, 192.168.9.20, 192.168.9.30 and if i am running this setup in 9.10 what about the other two hosts 9.20 and 9.30. what are the prerequisites to be run or installed on the other two hosts 9.20 and 9.30. I have just run the auto installer on the three hosts 9.10, 9.20, 9.30 and after that launched the setup in 9.10. The other two hosts are not connected if i am adding them in the list. Shall i need to start any processes to listen this setting on 9.20 and 9.30 ?

2) what is the username and password mentioned here? The auto installer doesn't ask me any password while installation. Is it the mysql database password of the databases on each system and is it unique on each host?

3) I have already a mysql database installed in 9.10 system previously. To set up a cluster with three hosts 9.10, 9.20, 9.30 is it required to uninstall any previous mysql databases running in those systems, because they suggested the usage of mysqld process comes with cluster setup ?