Please read these detailed instructions on how to use the Multi-Submitter: 

Here's how it works:
Scroll down to member's area and click "multi-submitter". It will ask you to make the payment of $1.50. You will then be billed $1.50 each month thereafter, unless you cancel.

Your membership level determines how often you can send mail:
Pro members can send every 72 hours, Platinum members every 48 hours, and Executive every 20 hours. Your ad goes out to ALL 600+ safelists!
Your billed $1.50 PER MONTH, NOT per send. This is the cheapest multi-submitter on the net!

After you "join all lists", With our One Click Submitter You Can Send Your Ads To Over 660+ Safelists & 600,000+ Members Daily with Only 1 Email Validation!
Then you are ready to send mail!
Now this is how it works, so you can make it work properly:
When you join all lists (at the bottom of submitter page), click the button only once. It takes a couple of minutes to join you to that many lists. Once it shows you as joined, log out then log back in. If you don't, it will read that you can only send mail every 400+ hours. Logging out then logging back in will fix this. Then you are ready to send mail! It will now be correct every time you log in.
As new lists are added, and you join them, repeat the logging out and logging in process.

I hope this answers all your questions. If there's anything that wasn't answered here, please send me a support ticket.
Thanks.