To have StreamElements run ads for you
Add the StreamElements bot as an Editor to your Twitch channel here
Create a timer with the response: /commercial <30|60|90|120|150|180> to indicate the ad duration. Also, select the time interval between ads.
Example: /commercial 30 (with an online interval of 10 minutes) - This means that every 10 minutes, a 30 seconds ad will be run.
To manually run ads
Create a custom command with the response /commercial <30|60|90|120|150|180> to indicate the ad duration
Example: !ad with response: /commercial 30 - This will run a 30 second ad everytime you (or any moderator) type !ad in chat