In order to take advantage of Nestio's StreetEasy Lead Sync tool, you'll first need to set-up autoforwarding rules for the email address to which your StreetEasy account is registered.
Your rules/filters should be set-up so that any email from email@example.com that contains "StreetEasy Listing Inquiry" or "StreetEasy Building Inquiry" in the subject line is being forwarded to the StreetEasy Lead Forwarding email address provided to within your Nestio account as specified in the article referenced above.
In Office 365 start by accessing your mail settings:
Select 'Inbox and sweep rules' from the 'Automatic processing' subsection:
Click the + button to create a new rule:
Set-up your rules such that emails received from firstname.lastname@example.org that contain the words "StreetEasy Building Inquiry" or "StreetEasy Listing Inquiry" in the subject line are forwarded to your unique Nestio lead-sync address. See this article for details on where to find this.
When the autoforward is successfully set-up your leads will automatically appear in your Nestio clients tab when they contact you via StreetEasy.