I want to add Fubo for their free trial offer, but don't want Roku to manage it. I forgot how that is accomplished.
Once you've created your account directly with the provider (Fubo in this case), you should be able to add the channel and then when it starts it should ask you if you want so "Sign in" or "Sign up" or something similar to those terms. Choose the "sign in" option. If you've ever had a subscription through Roku it could get more complicated as it seems some channels only offer you the option to start your Roku subscription again.