Hello @savtym !
Weebly does not have FTP, so it's not designed to have a file repository to which you can upload files to work with your site. In addition to the standard players in the Weebly toolbar, there are a number or players available in our app center you might consider. Also, you should be able to embed a player into a page using the EMBED CODE element without having to upload files.
Nonetheless, if you do wish to try it using the Assets folder, to find the actual URL for files there, try clicking on on of the image files that's already there, and then right-click on the image itself in the window on the right, where you'll be able to collect the URL so you can see how you would link to it. One thing to note is that if you change themes, the URLs for everything in the Assets folder will change as well. If you need assistance with determining what that URL should be for your site, please feel free to reach out to me via Private Message. Please include your site address and the email address you use to log in to Weebly in your message. Best of luck to you!
