You've got flexibility when it comes to reactions in a channel. You can:
Set one reaction type that applies to every video
Set a different reaction type for each video
Mix and match — a default for most, with custom reactions on specific videos
Reactions
To set a default reaction type for your entire channel:
Go to the Reactions tab of your channel setup.
Choose a reaction type from the dropdown menu.
Use the left-side panel to customize the reactions.
To override the default for a specific video:
Click the video you want to adjust to enter its setup.
Go to the Reactions tab on the video setup page.
Use the dropdown to select a different reaction type for that video.
Quick note: When a video is uploaded to a channel, its reaction type is automatically set to Inherits from Channel. If you change the channel-level reaction type, every video still set to Inherits from Channel will update — but any videos with their own custom reaction type will stay as-is.
Questions
To add questions to videos in your channel, check out our article on prompted questions.