You should be able to do it from the Acorn channel/app.
https://channelstore.roku.com/details/272ba82f0e179295b316d12896f9cdbc/acorn-tv
Don't try to access Acorn through "The Roku Channel".
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.