Step 1. Get the RF module working without Blynk.
Step 2. Get blynk app working without the module.
Step 3. Combine the codes.
Your main code does not go into the void setup() section. If will either be in the void loop() or another section dedicated to Blynk.
There are a lot of Blynk examples so you could start there. You should start simple. Start with lighting a led from the app.