Please add or correct for clarification.
From experience it tends to go this way:
Received - meaning it has arrived at CGC and placed in a line in order to be...
Verified - where the issue is verified it matches what is listed on the order form and placed in line to be
Scheduled for Grading - it is now near the front of the line and soon to be grabbed. If it is a single issue, it'll be quick. If part of a bundle then expect the status to change to
Grading - it's when its being checked over, looked at, etc
Graded - tends to be the next step where it is again in line to be encapsulated and for Quality Control to go over it, just before being
Shipped/Safe - when CGC boxes them up and sends them off. They use to have an option to place them in a safe for local pick-up, alas no longer it seems.