I would not suggest hosting on dropbox and such. Seriously impacts load times.
Try to host on cdnjs.com or jsdelivr. (google and see how to)
to use that script in your webflow project. You would just need to drop a html embed where you need it to appear and reference the script like this;
<script src="//cdnjs.com/path-to-your-script.js" type="text/javascript"></script>
Thats all.