How to get to pont aven in france?

The answer to your third question is yes, lots (cars, walking, horseback riding, etc). However, assuming that you mean mass transit, the closest station I know of is Rosporden station which is about 16 km away from Pont Aven. You can go to sncf.com/en and see the train schedules but there is at least one train per day that does not require you to make a connection. Usually though you take the TGV to Rennes or Quimper and change to a local (TER) train. Then take a taxi from Rosporden. I am sure there is probably a local bus from Quimper and Google is your friend for that.

Then where can I buy the bus ticket and get the ticket in quimper?

You buy the ticket at the bus station which lucky for you in Quimper is the same place as the train station. You need bus line 47. I am not sure how frequently it runs. Go to via00.29.fr and click on Horaires and then enter your travel date and the line number and you will see the schedule. Do you speak or read French? if you don't, it will be a challenge but doable. I know of no non-French version of via0029 site.

Thank you so much!