Hello! Welcome to Feng Office!
1- When you create your email account you may select the workspace where you wants the email messages to be
2- You should go to Administration>Cron events, and look for the "Check mails" options. (check
this thread, last page, to see how to run the Cron.)
3- If you download them with the Cron, all of your emails will be downloaded. If you check them once every while, you should go to Administration>Configuration>Mailing and look for the "Email fetch limit" option.
Best!
Francisco