How to defrag a computer

Not sure what this means

The image you were given does not exist in 8.1.

I have advised you how to access it.

And when you access it through the Charms Bar it gives you a Windows called "Optimize Drives" with their status set out for you.

I happen to use 8.1 when I am posting here.

HDD, Hard disk drives, can be defraged. Defragment Definition (techterms.com)

SSD, Solid State drives, are Trim. TRIM Definition (techterms.com)

Not sure what this means

I see you are still using OS 8.1. Do you have HDD's or SSD's?

I don't know anything about Windows 8, never used it, but have you checked the Control Panel, if one is available.

Click on, tap, or activate image to enlarge it.

It is an automatic process.

Optimize Drives, previously called Disk Defragmenter, runs automatically on a weekly schedule. But you can also optimize drives on your PC manually.

To optimize drives manually

1. Open Optimize Drives by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the uper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Defragment in the search box, and then tapping or clicking Defragment and optimize your drives.
2. etc.

To change the optimization schedule

1. Open Optimize Drives by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the uper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Defragment in the search box, and then tapping or clicking Defragment and optimize your drives.
2. Tap or click Change settings.  You might be asked for an admin password or to confirm your choice.
3. etc.