You can create new Custom Fields that can be used as Personalizations
From the Manage screen, click on Fields and Data, then on Add to Create a Field.
Upload a CSV file with the data you want populated into your Contacts. Pick a Unique Identifier column (such as NRDS Number or Email), then connect the CSV Column to your new Field. Click Finish, and then click on the Progress Bar once it's done.
You can now use that new Field as a Personalization in your Messages!