Service Account permissions and rights

Hi,
Does anyone have a link or can you tell me what permissions, group membership, and rights the 3 service accounts need?
The Acronis documentation says we need 3 service accounts which I did. But then it says this one or that one needs to be in the Administrators group - Which group??? The client? The Management Server?
I'm having all kinds of issues with my backups. Support of course says just use domain admin credentials which we refuse - bad practice, and always the "easy way out for software vendors".

Can anyone tell me, which groups (and on what machines) the Agent, Management, and Storage accounts need to be members of? And which services need to run which accounts? And which local rights?

Yes, normally, I would just read the manual, but their manual is clear as mud, the support tells you something totally different.

Thanks in advance - much appreciated!