EE site sync with private key and password

[digit-c]

👋 Hi everyone!
I was wondering if there is any further documentation regarding EE SITE SYNC online? I'm trying to use my local EE site to deploy on the live EE site using the SYNC command but I get an error "Unable to SSH to xxx.xxx.xxx.xxx" because I need to enter private key location + password
Would you be able to help by any chance? Ideally, I would like to be able to setup multiple dev/staging and sync up and down between various ee sites

thank you!