You have to start with a good book. Here are a couple good ones I've used:
A Picture Book of Martin Luther King, Jr
Then after you've read a good book or two to build schema...then you can move on to planning and plotting and writing and interpreting.
Here is a freebie I made...this is a sample of what the finished product could look like. It is on my TpT store with the writing template. Feel free to use it :) Click HERE to download.
Free coloring page on TeacherVision
This is a good video on Brain Pop (I had never found this site before. It's cool!)
Check out this Fingerprint Peace Dove art project. It's amazing!
This site has a historical narrative for you to read if you are rusty on the details of Martin Luther King Jr's life.
Well, that should get just about anybody started. If you still haven't found what you need, then pop over to TpT and search for free Martin Luther King stuff. There is quite a bit more on the site.