Imapsync is a (PERL?) script you download, and then run it passing parameters.
If you need OAuth, and it seems so since you want to sync a Google account, you have to download some more files that help you obtain an access token for Gmail.
But as far as I remember, there are no config files needed to run it. Infact I am cron running it every 5 minutes to one way sync an IMAP account to Office365 (needs an OAuth token too, and a second script to refresh the token every hour)
Feel free to ask for more, but I cannot guarantee a timely response.