First navigate to your Account & Billing section from the bottom left menu:
Click on the Subscribe button:
First add your credit card. You are just adding a card to your account, nothing is going to be charged yet. Add your name, card number, expiration and CVC.
Once added click Save New Card:
Now you should see your card added with last 4 numbers displayed. Click on the drop-down on the right to choose your plan:
Check the box next to the plan you want:
Now all that's left is to click Subscribe:
That's it. Welcome to Spotlightr!