Klik nama diska yang ingin di-defrag. Klik Defragment Disk atau Defragment Now untuk memulai proses defrag.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
For example, if you want to defrag your computer's main hard drive, select "OS (C)." Your computer will take between several minutes and several hours to defrag the drive depending on its size and current fragmented status.