Hook up with someone who does fly fish, or go to Cabelas or Bass Pro on a Saturday morning for free lessons, or join a club or contact a professional fly casting instructor.
Should none of the above suit you go to YouTube and search for fly casting and fishing instruction, however this is going to cause a lot of frustration and a longer learning curve.
In the beginning God created. Gen. 1:1
All things were made by him and without him was not anything made. John 1:3