Hi @toverstreet ...
I think we need a bit more information from you. What do you mean by "external link"? Do you mean that your teachers are trying to add third-party external tool LTI apps from the EduAppCenter? If that is the case, most of these external apps have some sort of cost associated with them. (Though, you will find a handful of free apps here, too.) Once the app has been purchased, you would get a Consumer Key and Shared Secret (think of this sort of like a username/password) from the developers along with instructions on how to incorporate the app into Canvas. Most times, these apps are installed at the Canvas account level so that the app is available for all Canvas courses vs. at the course level (where the app is only available for one course). If you are a Canvas admin at your school, there are a handful of Guides that you can look through for External Apps (LTI) using the link I've provided.
I hope this information will be of help to you in some way. Take care, stay safe, and be well.
