What is your case? (There will either be a mounting solution in the case or a mount with fitting screws.)
If not, the drive SHOULD be delivered with a small bag of screws.
If neither is the case, use two sided tape (strong) or another double sided solution and plaster the thin, non heat generating drive to the back of the wall of the case, or any flat surface you can find in there which isn't too near heat generating components.
This is the beauty and versatility of an SSD.