Create a Whatnot seller account and get approved for livestreaming
Open Whatnot and go to the live selling or streaming setup
Choose the option to stream with external software or RTMP
Copy the stream URL and stream key from Whatnot
Open OBS Studio on your computer
Go to Settings
Select Stream
Set Service to Custom
Paste the Whatnot stream URL into the Server field
Paste the Whatnot stream key into the Stream Key field
Click Apply and OK
Add your camera source in OBS
Add your microphone source in OBS
Add any display, image, or product sources you want to show
Arrange your scene in OBS
Set your video resolution and frame rate in Settings
Set your audio levels and test your microphone
Click Start Streaming in OBS
Go back to Whatnot and confirm the stream is connected
Check the live preview and audio on Whatnot
Start the sale or live show when ready
Monitor chat, video, and audio during the stream
End the stream in Whatnot and then stop streaming in OBS