Do I have to put the prototype build of the game am going to make on itch or just a video of it or something?
For the Ideation phase, we recommend uploading a PDF showing all of your documentation, concept art and mockups, and screenshots of any "toy" prototypes you've created. It's strongly recommended that you don't start working on the final project during this week, so a PDF should suffice for this week.
Next week's sprint (and the two after) it is recommended that you submit a build at the end of the week.