If some of you desktop icons are missing, see solution 1. If you have no desktop icons, see solution 2.
Solution 1
If some of you desktop icons are missing, they may have been deleted. Ones that were always there since you first logged on will repopulated after you restart. Others can be recreated using the this solution.
Solution 2
If you have no desktop icons there are only two possible reasons. Most likely, your desktop icons are hidden. To check this, right click the desktop, hover over the "view" option and a drop down menu will appear. On that menu make sure "show desktop icons" is selected. If selected (check mark is by it) then you should see all your desktop icons.
If it is selected and your icons are still missing, your icons were likely deleted. You can rebuild your icons with a restart and creating shortcuts. See Solution 1 for more details.