Im assuming you have winrar so what you do is right click on the and you should get an option to Add to archive then hit OK
You should be able to right-click and go to 'Add to archive...' and then just hit 'okay' if you want it in 1 file. If that option isn't there, you can open winrar and go to File > Browse for folder > and then click the folder > hit 'ok' > hit the 'add' button on the upper left hand side > click 'ok' and let it run.