Look at 2etime’s YouTube channel. There should be enough there to get you going and then some. edit: the programming language should not matter much, but if you insist, I do think that I have seen C++ tutorials on YouTube as well.

I am shocked... I was looking into the Launch Pad, I was long clicking on the Xcode icon when suddenly App Store woke up and made one Jump signalling that the installation was complete. It now says 'open' instead of that spinning circle. I do think it actually must have completed in that exact instant, but I am mentioning it here in case it has any relevance. If you struggle with this, please try to long press on the icon in Launch Pad to see if that completes the last step of the installation.