It’s not obvious, I can tell you that.
For a recent article on CHKDSK, I carefully timed taking a few screen shots of CHKDSK as it was running in a virtual machine so I could capture the results.
Besides not being useful to the average user, it turns out that was overkill. You don’t need to go to those lengths to get CHKDSK’s output. In fact, you can almost ignore what it displays on boot.
You can get the results later, much more easily.