Congratulations on wanting to learn how to create a lead sheet. You've come to the right place!
There are many musicians who never take the step you are taking. Many never make it a goal to be able to write their own lead sheets.
You are entering into the territory of professional musicians...or you
may be a professional musician who is taking steps to increase musical literacy
Wonderful and good for you!
I salute you!
To learn how to create a lead sheet, I recommend my eBook "How to Write Your Songs Down!"