You should be asked for your password ONLY when attempting to make payments, not when opening your wallet each time.
Regarding Public and Private keys the public key is your wallet address where you send coins to and private keys are what you use to sign payments with, it essentially proves you own the coins in that address, so never share it with anyone or they will be able to spend your coins. Check out these two videos to walk you through the steps of finding/explaining them in more detail:
Public and Private keys Explained: https://www.youtube.com/watch?v=67uW07QDHxE
How to Export/Import: https://www.youtube.com/watch?v=TevLN_k-GWA