Problem with changing to high gear on the front derailleur on my new Bianchi Spillo Rubino Altus Rigid It's a 24 speed bike with 3 gears on front (Cranks PROWHEEL 48/38/28T) and 8 on the rear. I rode it today and when I was moving the front gear to 3 to move the chain to the large ring I have to press the shifter hard and it does not always work. Sometimes when I move it from 1 to 2 that also does not work.

Can you suggest what might be wrong and how to fix this.
You need to adjust your front dérailleur/cables/shifter, there are multiple tutorials for this on the internet if you are mechanically inclined and have basic tools.

Or you can pay for your LBS (local bike store) to fix it for you. 

I have used this youtube video for good effect a few times:


                
            

Mind you, with top of the line brand new components it is much easier than potentially old and rusty equipment.