You must install License Manager in order to install the JoomSuite User license through the License Manager tab of JoomSuite User component. If License Manager is not installed then you will have to manually install the JoomSuite User license.
To install License Manager:
2. Scroll down the Web page and click the License Manager link  as shown in the following figure:
3. Scroll down the Web page that appears after clicking the License Manager link and click the com_jslm.v.3.4.zip link , as shown in the following figure:
4. Download and save the License Manager installation file.
5. Visit http:/localhost/Joomla/administrator. Enter valid credentials and log into Joomla back-end.
6. Navigate to Extensions-> Install/Uninstall. The Extension Manager page appears.
7. Click the Browse button in the Upload Package File section and locate the License Manager installation file.
8. Click the Upload file & Install button.
License Manager is successfully installed.