France travel problem

Firstly , thanks for your information and help

I am planning to go france and i will stay in the hotel which is in Nice
and travel for 3 days only. So i am in trouble about how can I spend the days in France more efficient.

I want to know where is the most famous area say the market and beaches and shopping mall in Nice and Cannes and Grasse.

And i also wanna know more about the transport problem. How can i go to Cannes from Nice then From Cannes go to Grasse and finally back to Nice.

I would also like to know more about the costs, is there any one day train ticket or bus ticket? Of course as bargain as possible Please.

I have no idea what place i can visit (the popular place) and what activities i can do in the beach. Also , which is the most popular beach in Nice ?

Thanks for your help and information again , Thanks so much>,<