Welcome to the Blynk forums. I suggest starting here...
Pick your board, communication method and a sample sketch - probably something along the lines of GettingStarted/PushData.
Then dig through http://docs.blynk.cc/ for more details on the various commands.
Then, once you have had some progress and hit a snag, we can help. But be aware not many are going to write your code for you
Also... and very important! Please read this before posting any code.