To log in to TIDAL with a Squeezebox account, download TIDAL.
You can find full installation instructions here.
For support or any questions about ickStream and the Squeezebox, in particular, you can send an email to Support@ickStream.com or view their Community Forum.
If you have any playback trouble, login to ickStream here. In the Services section, remove TIDAL, then re-add TIDAL to the account.