cd?
please visit microsoft site, download the windows 10 download tool
have in hand a 8 gbs usb thumbdrive for this task
do you have a license for this windows 10? you need to download the right version with the tool i mention, if you download the wrong one, install it and the license you have is for other version, you will need to download and install the other again
before doing a windows instal is important to have backups of your personal files like dsktop files, downloads, my documents, all that files you can't replace with a installer