If you did not add Lync service for your users when you created them, you will need to go into the Customer Control Panel and add Lync to your users to enable it. Follow the instructions below to achieve this.
1) Log in to your Customer Control Panel and select the correct subscription from the drop-down menu at the top of the page.
2) Navigate to the Users tab. You will see a list of your service users. Find the user that you need to add Lync for and click their Display name.
3) Click Add Service at the bottom of the page.
4) Select the checkbox next to Lync.
5) On the next page, you will see how many of each type of license you have available. Select the type of user you would like to enable for this user and click Next.
6) Confirm your selection on the next page and click Finish.
You will see the User Info page again, and Lync will now have been added.
This completes the process of enabling Lync service for your user.