To start installing an RDS CAL, you must first open the Remote Desktop License Manager.
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Now right-click on the server name and select Install license in the submenu.
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In the next step, skip the start page by clicking next and selecting Complete Product Purchase on the second page and then clicking next.
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Now enter the product key (there may be more than one) and confirm with Continue to complete the installation of the RDS CALs.
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