Hello Michal,
The next step is to take a look at the example projects in the BLE v1.3. You can use the Keyfob or simplePeripheral as a template for setting up you own profile.
In the Keyfob project they use the ADC for measuring battery voltage. You can use the same function calls in your profile. The batteryService.c found in the profiles folder will also aid in your understanding.
Yes, that's it. Once you understand the concept, it is actually straight forward and you will be doing a lot of cutting and pasting. If your project requires strick timing, or large amounts of data, then it gets a bit tricky.
Thanks