In need of help /France/ Anything and everything

Hello there all people from France or at least knowing about France more than I do!
I'm going on an adventure soon, but I don't speak a word in French and I know nothing about French transport. Could you give me a hand?
I need to get to Forcalquier (Or a city close to it -Oraison). From Poland to France I will get by a bus and I can choose my destination. I would like it to be Grenoble, Marseille or Nice (I will post list of other cities downbelow). The thing that determines my choice of city is direct connection between particular city and Forcalquier/Oraison. Is there any train/bus/other that I could use, without being forced to change during the trip? I can't use hitch-hiking (auto-stop), for an obvious reason (no hablo español).
If you could also tell how much (more or less) would cost me a ticket, according to the connection I would choose, that would be great! Or at least, could you tell me, if I'm a student in Poland, can I buy a ticket with student discount in France?

Merci beaucoup for any kind of help!

List of cities I can choose as my destination on trip Poland->France:

You want to go to Forcalquier from Marseille right?
There is a bus, the number 25 which goes there.
You have to take it at the train station "Saint Charles", and it will brings you at Forcalquier. You have one at 11h and another at 17h05 or 19h45.

Go check this link, there is further informations.
The price of a ticket is 18,60€ (Marseille-Forcalquier)

I hope my message is clear, you can message me if you need more informations, I think that I will be able to help you !

Yes, it is clear and incredibly helpful! Thank you very much. I think I will start my trip in like two weeks and I'll be thankful for your help, in case any other questions appear. Thank you once again! <3