I thought there was a problem with it too, but I was wrong.
Go to your CS50 courseware and take a look at Problem Set 0.
Don't forget to do these things before submitting :
Your project must have at least two sprites, at least one of which
must resemble something other than a cat.
Your project must have at least three scripts total (i.e., not necessarily three per sprite).
Your project must use at least one condition, one loop, and one variable.
Your project must use at least one sound.
Your project should be more complex than most of those demonstrated in lecture (many of which, though instructive, were quite
short) but it can be less complex than, say, Pikachu’s Pastry Catch
and Ivy’s Hardest Game. As such, your project should probably use a
few dozen puzzle pieces overall.
Once finished with your project, click See project page in Scratch’s
top-right corner. Ensure your project has a title (in Scratch’s
top-left corner), some instructions (in Scratch’s top-right corner),
and some notes and/or credits (in Scratch’s bottom-right corner). Then
click Share in Scratch’s top-right corner so that others (e.g., your
TF!) can see your project. Finally, take note of the URL in your
browser’s address bar. That’s your project’s URL on MIT’s website, and
you’ll need to know it later.
At the end of the page, you'll find a part How To Submit
Here's what it says :
To submit this problem set, visit http://cs50.edx.org/2015/psets/0/.
You’ll find that a few questions await. Be extra-sure that your
answers are correct, particularly your project’s URL on MIT’s website,
lest we overlook your submission!
CS50 collects quite a bit of data for research purposes. Please
forgive the length of this first problem set’s form! In total, the
form will probably take 30 or more minutes to fill out. Not to worry
if you finish shortly after the problem set’s deadline, so long as you
start before the deadline. Future problem sets' forms will be much