have been asked to check the following :
-the stepper motor,;
- butterfly case;
-throttle position sensor
-TDC sensor
- camshaft sensor.
problem is. i don't know where they are located. so..
alittle help would be apreciated

Sounds to me like you're in dire need of a repair manual. A 'Haynes' will set you back maybe 5 pounds. I suggest you go on eBay an buy one for your specific Fiat model - You REALLY need to have a look in the repair manuals, my friend, as there are bound to be so many other questions following - E.g. 'how do I clean this and that, how do I remove them' etc etc.
Check this post to get the general idea (e.g. the last post):
https://www.fiatforum.com/bravo-brava/210969-need-original-manual-book.html?p=2734682

You're welcome to ask here again, of course, but the manual is step one, really