Please remember that it may take a while for the SSL certificate to be issued. Until now, you need to add the process of transferring this SSL certificate to the system.
Usually the Install button appears within 2 hours from its confirmation, then the Install button also appears in the Client Panel.
If that time has passed and you still do not see the Install button, it is possible that your domain has added CNAME records from your previous free certificates that hold back the issue of a paid SSL certificate. In this case, please contact our Customer Service.