Create usb bootable device

Step 1:  

goto rufus website and download rufus software

Download now 

Step 2: 

open rufus software

Step 3: 

Select pen drive you want to make bootable

Step 4: 

select image file of windows setup you downloaded

Step 5:

click start to begin

Step 6: 

After finishing the coping process. Restart computer and enter bios setup. press f2  or relevent key to enter bios setup during start up.

Step 7: 

Change boot order by selecting first boot device as usb device. and second boot device as hard drive. don't forget to select hard drive as second boot device.