First, if you don't already have a Roku account, go to roku.com and set one up with your chosen email address.
Then, do a factory reset on your tv to erase all its settings and set it up like it was a new set, and log into your roku account. I have separate Roku devices, not a Roku tv, so I don't know the menu path, but on my devices Factory reset would be under Settings > System
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X