Modern PCs no longer use floppy drives. The information is retained here for reference purposes.
The next step is to install your data storage devices.
Unpack the FDD (Floppy Disk Drive). Make sure at this stage that you have your anti-static measures in place and even briefly make contact with both hands on the metal of the case to make sure.
You will notice, on the front panel of your PC case, there is an opening the same size as the floppy drive's front panel (if there is a plastic cover plate fitted, just gently push it out from behind.)
Slide the floppy drive into the opening backwards such that its front panel becomes flush with the front of the PC case. Clear any obstructions to this insertion from inside the case if necessary.
Once fully inserted, there should be some fixing holes inside the case such that you can secure the floppy drive to the case. Use the fine threaded screws for this.