Upgrade to 7.23 announced from 7.1 ... how do I tell what version I have?

I downloaded the Zip, however there are no instructions anywhere how to do this upgrade. Am I just missing them? Also how do I tell if I have 7.1 or what version of SuiteCRM I have currently so I know I am installing the right patch?

Thank you!

You can find the version by mousing over your name in the top right corner and selecting “About”.