To start, click the advanced search link underneath the search bar from the left-hand menu.
A window will appear in the center of the page. Click Add Criteria to begin. From here, you will be prompted to choose a variable that's available in the selected programs (to adjust the programs you have selected, click out of the window and check or uncheck a program at the left). Next, you'll be able to identify how you want to search within that variable (equals, does not equal, contains, does not contain, etc). Finally, you will select the value(s) you are searching for. After the search criteria has been set, you can add on additional variables by clicking Add Criteria. If the search is complete, click Search to view your results.
In this image, I've added criteria to filter the contacts by GPA and advisor.
After your results load, click the white downward arrow next to New Message at the top right, then click Send to current results.
A new window will appear in the center of the page for you to compose your text message. You can include contact profile data in the message content to personalize your message. Click the tag icon in the bottom right of the message box and choose the field you want to include. The field will be inserted where your cursor is, and will automatically be followed by a space. You can include as many fields as you would like in a message.
Once you type your message, either send now or schedule for a future time by using the Delivery Date options at the bottom and click Next. Your message will not be sent or scheduled until you click Send on the Confirm New Message screen.