There are two methods to add subscribers to your campaign.
1) Keyword Opt-In (most popular)
Subscriber can opt-in to your campaign on their mobile phones by texting your campaign's unique keyword to the 5-6 digit phone number (short code) assigned to your account. To setup your keyword, click here.
2) Website Opt-In
For instructions on how to add subscribers through a website, point of sale, etc., check out this post.
Telephone Consumer Protection Act (TCPA) Compliance Notice
In order to help businesses comply with TCPA federal laws, Tatango does not allow uploading or importing of phone numbers, except in the case of businesses moving SMS subscribers to Tatango from another SMS provider.