Hi Woozle, welcome!
The prompt each Monday is to make any card of your liking based on the prompt. So if the prompt is a theme like week 1 - using stash you've been itching to play with, week 2 - making a card based on the colour palette shared, your card needs to reflect that prompt. As an added challenge you can use the same prompt to make a Christmas card each week and build up your stockpile ready for December.
So this week's prompt is a card sketch - you make a card of your choosing based on the sketch plus a Christmas card based on the same sketch if you want to play along with the Christmas aspect of this challenge. :)