To help you a little bit, I've searched for some sites to help you out.
For writing your song you can use:
If you don't understand a word or sentence, just put it in google Translate:
I almost forgot, I also found some video's to help you make the song with the melody. They give good information and it really is fun to watch. I hope you make a good song!
How to write a song: Step 1
How to write a song: Step 2
How to write a song: Step 3
How to write a song: Step 4
How to write a song: Step 5