How to Upgrade Old Mac Pro 2009 OSX Snow Leapard to OSX El Capitan?

[Gust]

So I recently brought a 2009(I think 2009)Mac pro and after a little bit of trouble got it working and connected to internet. Now I noticed that it has a outdated OSX and it can't just straightforwardly upgrade to OSX El capitain due to lack of supported firmware. Yet I still would like to have the latest OSX on it and am aware there are "techniques" to doing this but Not sure where to exactly begin, not being familiar with OSX before this.

Also know my Mac Pro holds two Hard Drives one with snow leapard and one with no OS(I assume, idk how to check for sure), If possible I would prefer to install the El Capitain on the one that has no OS to not risk leaving myself OSless.

 

[Spawn_Dooley]

Hi Gust have you read through this?

Upgrade to OS X El Capitan

To check to see if the empty drive is ready you can 'look' at it from Snow Leopard using Disc Utility. See if the drive shows up in the left pane. If it does, click to highlight it then look at the information displayed to see what the story is with it. How it's formatted, it's size etc ...