In order for SelectHR apps to be available inside of Access Evo (Previously Access Workspace), your Access Evo Organisation needs to be set up to use the SelectHR with Apps subscription, rather than the Access People subscription.
SelectHR with apps is a new item of functionality, so not all customers will be set up with this subscription. Support will be able to confirm that you are set up with the correct subscription.
Please raise a new case online to confirm.