just press the green flag. If the list ends up having lots of numbers in it (like over 300) you may want to reload the page rather than clicking the green flag. The green flag will clear the list by repeatedly clearing the first item over and over again until the list is clear but that can take a while so sometimes it is quicker to refresh the page. or play in turbo mode and removing the items in the list is instant.
I created a version of this at school and at school we use offline versions of scratch so we can't upload anything. This is a remake purely from memory without some of the features that we had to put in at school. Comment below if you want me to add a start from question that asks you what number to start from. If there are enough people who want it I will add it.