If record is listed in your system with the correct e-mail address, any incoming messages that match that e-mail address will download into the Activity Timeline of that record.
If a record is not listed in your system, but you want to associate message to that record, you can use the Connect with a Record option.
While the e-mail message is open, select the type of record by clicking the dropdown arrow.
Type the name of the record and select it when it appears.
The e-mail message will then be associated with the record and will be placed into the timeline.
To associate the e-mail message to a new account and opportunity, while the message is open, click Add New Deal.
This will allow you to create a new account/opportunity and link it to the e-mail message.