how do I download my free Logic pro X upgrade

What do you mean by "free upgrade", upgrade from what?

If you own Loic Pro 9, then there is no "free anything". Logic Pro X is a new app with a new price tag $199. One you bought it, any update is free so far (currently v10.2)

Hope that helps

Edgar Rothermich - LogicProGEM.com

(Author of the "Graphically Enhanced Manuals")

http://DingDingMusic.com/Manuals/

'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

Under the Apple Menu is a command "App Store", which opens, you guessed it, the App Store.

Search for Logic Pro X and you should see an update button. But, make sure that you log into the App Store with the same User ID that you used to purchase Logic Pro X in the first place. That Apple ID is basically your purchase license.