by Hira Thapa.
Thank you so much for your generous help. I found all the downloaded files in the moodledata/temp folder. I found many. That means I had tried many times and all were located there. There are more than five hotpot files, and similar others like essential, attendance and I tried to delete all of them except one plugin module folder each. But the delete button on the menu is inactive due to which I cannot delete the downloaded folders with codes, numbers and letters. I can delete only the inside contents - 'contents' and 'source' only.
Regarding managing admin tooIs, I checked the admin tool as the way you navigated me. But unfortunately, there is no other buttons to click for further process except the 'delete' button. Here is a screenshot:
