Add New IDS Monitor Alert
Email Recipient Alert Priority Notify From Notify Until
[EMAIL_ADDRESS]
Existing Signature Signature Contains
[SIGNATURE_LIST]

Note, by default, all alerts are P-2 / Yellow. If you choose to be notified on P-2, expect to be mailbombed if you are on a busy network.
The preferred method is to hand select P-1 / RED signatures through the Configure Snort Rules option so that you only receive alerts for the "important" IDS alerts.