i guess you acer laptop must comes with the factory backup image. You have to press certain key during pc boot in order to enter the restoration screen.

if you don't want to install the default acer system image (because the default system image is quite obsolete). Let's say you was downloaded the latest Windows 10 v1803 ISO and decided to do a clean install for your laptop. You must first to backup everything important such as your pictures, video and music into your external harddisk.

You need a tool "Rufus" and prepare a minimum at least 8GB USB thumb drive to copy the Windows ISO into you USB thumb drive.
You only can choose to boot install Windows 10 from the boot screen (usually is pressing F8 during windows boot).