Go to Setup --> Accounts and set up both Incoming and Outgoing email.
Outgoing Mail - SMTP Account
You will need your email hosting server configuration, which should include the server name, port, and TLS or SSL options. Your email is typically also the username used for the email account. Common ports are 587, 465, and 25.
Incoming Mail - POP3/IMAP Account
Your email hosting server should also include a configuration for POP3 or IMAP -- we recommend using IMAP.
Here's a video: