Aside from capturing clips from your phone, you can upload clips directly from your android device! 

Open the Medal app and tap Post
From the dropdown menu, you will be able to select My Clips and Camera Roll My Clips - Clips you have taken with Medal Camera Roll - Videos stored on your device (Requires Mobile Number Verification)
From here, tap on the clip you want to upload and then tap Next You can upload multiple clips at the same time by tapping on Select Multiple button and then tapping on all the clips you want to upload (Up to 5 at a time)
On the final screen, you will be able to customize your clips information. Select if you want your clip public or unlisted Give your clip an eye catching Caption If your selected clips is from your camera roll, you will be asked to select which game it is in the Clip Category box Tag your friends and add any hashtags Once you have finished adding information to your clips, tap Done
When uploading multiple clips, don't forget to swipe to your other clips to add captions to those!
Medal will give you notifications of your clips upload progress and when it finishes!