You want to save the wallet.dat file. Just to go "File" then click on "Backup Wallet" and save that file. I would rename it to something else if you're backing up multiple wallets. Also back it up on multiple devices like memory sticks and keep them in different locations.
Thank you. So according to you I just need to save wallet.dat file and rename it e.g. "ethereumcash" and save backups multiple times.
Alrighty I just did that. So no other folder or files needed to save.