Q: The "other" swells, taking up all my storage when i try to activate Itunes match on my Iphone 6 Plus. Please Help!

Hello there, chadmon1997.

It sounds like you are wanting to setup your iTunes Match on your iPhone 6 Plus.  The following Knowledge Base article outlines the steps on how that works on an iOS device:

Use iTunes Match on your iPhone, iPad, iPod touch, or your computer

On an iPhone, iPad, or iPod touch

1. Tap Settings > iTunes & App Store.
2. Sign in with the Apple ID and password that you use for iTunes Match.
3. In the upper-left corner, tap Settings.
4. Tap Music.
5. Turn on iCloud Music Library.
   

iTunes Match replaces the music library on your device with your iCloud Music Library. (If you're also an Apple Music member, you have the option to merge your music library instead of replacing it.) Your device might use cellular data for this download. Check with your wireless carrier for fees that might apply, or go to Settings > Music and turn off Use Cellular Data.

For an overview of all the service entails feel free to review this:

iTunes Match. All your music. Where and when you want it.

Thanks for being a part of Apple Support Communities.

Cheers.