Ghost 15.0 New User. Re: Backups and incremental b/u's

I'm new to Ghost. I created a backup of C:\ and system files.  This backup is about 2x the size of the file> Is that normal?

Also, at this size I do not have space to backup and have 2 or more restore points. I have set restore points to one. I have not noticed any incremental. How often do they occur (I selected increment option). I read through the user  .pdf and find it somewhat unclear. I'd appreciate any advice/clarification. I'm just trying to have a simple backup with a manual  backup periodically.

Thanks