How to send mail when using offlineimap?

I've only ever used GUI mail clients like Thunderbird, and want to try using offlineimap with alpine. However I'm confused about how it all ties together. As I understand it: > Once I configure offlineimap with my accounts, it will go to every respective server and use IMAP to mirror my mails to a local folder like ~/mail/gmail. Presumably I can then use any mail client to read these emails, and if I make changes to them (such as marking as read or moving between folders) they will be pushed to the server the next time offlineimap syncs. But what about sending mail? I'm a bit fuzzy on how email works, however, it seems like: >IMAP is just for downloading/uploading mail to be stored on my mail provider's server. So IMAP can't actually send mail. Mail is sent using SMTP. In many clients, when you click "send mail", what actually happens is that the mail you compose gets sent through SMTP *and also* the mail client saves a copy of the mail to the "sent" folder of your account, which will be propagated through IMAP. So my questions here are: 1. Is my understanding above correct? 2. If I use offlineimap, who will actually send my outgoing mails through SMTP? Would I set up some separate "send emails" program that will periodically check my "outgoing" folder and send everything in there via SMTP (how will it know which SMTP server and account to use)? Or will I still have to set up SMTP server/credentials in alpine?