There are a lot of websites and services that allow you to upload your files for free, and make them accessible via a link. Feel free to choose whatever website you prefer. I found www.docdroid.net quite easy and user friendly. Just upload your resume (preferrably in a .PDF format) and you are good to go!
Just follow the steps from the website, and you should have a link at the end with which you can access the resume. If you want to check again if the link works, just open it in a new browser window and see if it works!.
Just copy this link and paste it into the form field! Your Goodmatch page will now have a "Show full resume" button that will open up your resume, so that they can explore more details about you. Good luck!