How can I install a clean version of el capitan?

[jeanvigo]

Hi guys
I am probably asking something stupid, but I don't know how to do it as I have never done it before.
Basically I have a middle 2011 macbook pro with el capitan installed, it has been a trusted partner in crime but at this point I would like to install again the operative sistem and format the hard disk. I have never used time machine, so I don't have any saved version. I Have all the data backed up but where do I get el capitan and how I install it?
Thanks in advance

 

[ZapNZs]

With clean installs, I have used the USB method where you backup all files-->download El Cap-->make a bootable USB installer with El Cap-->boot into the USB installer-->erase all contents on the startup disk-->run Disk Utility-->then Install Mac OS X from the USB installer

This may be of use
https://www.lifewire.com/perform-a-clean-install-of-os-x-el-capitan-on-your-mac-2259940

El Cap can be downloaded from the Mac App Store - it should be available under a 'Purchased' tab, where you can download it. You will get a message telling you that you already have El Cap installed - just click the message that allows you to download it again

 

[jeanvigo]

With clean installs, I have used the USB method where you backup all files-->download El Cap-->make a bootable USB installer with El Cap-->boot into the USB installer-->erase all contents on the startup disk-->run Disk Utility-->then Install Mac OS X from the USB installer

This may be of use
https://www.lifewire.com/perform-a-clean-install-of-os-x-el-capitan-on-your-mac-2259940

El Cap can be downloaded from the Mac App Store - it should be available under a 'Purchased' tab, where you can download it. You will get a message telling you that you already have El Cap installed - just click the message that allows you to download it again

thanks a lot
that answer my question and the guide you posted will help me step by step