This article describes how to install Swarmia without using GitHub Marketplace, which is in some rare cases necessary
For some organization types, GitHub does not support installing apps from the GitHub Marketplace. Sometimes there have also been bugs on GitHub's Marketplace preventing the installation of the Swarmia app.
If you are facing these issues, you can alternatively install Swarmia directly from this link: https://github.com/apps/swarmia/installations/new. There is no difference in functionality when installing via the marketplace or via this link.
Make sure to choose your organization as the target; Swarmia cannot be installed on personal GitHub accounts.