The VSTS Artifactory Plugin is an extension for VSTS and is available for download by account holders from the VSTS Marketplace.
To install the VSTS Artifactory Plugin:
Sign in to your VSTS account and go to the marketplace. You can find the plugin in the Build and Release section where it is named JFrog Artifactory Integration.
On the VSTS Artifactory Plugin page, click "Install".
Select the account to which you want to apply the plugin and confirm installation.