Serato Video is a separate add-on program which runs alongside Serato Video. Once you have purchased a licence for Serato Video from the Serato Store follow the below steps:
To enable Serato Video, login to your My Serato panel in Serato DJ.
Click the My Products tab & make sure you have Serato Video activated for your computer.
Go to Setup > Expansion Packs > Serato Video and make sure you have Enable Serato Video checked.
A Video button should appear at the top of your Serato screen. You are now able to use Serato Video in Serato DJ. Click on it to expand the Video tab.