Very carefully 
It's real glass, and surprisingly heavy...
First you need to remove the plastic strips on top & below of the glass. Push the end of the strip in from the front of the TV (it should move easily 3-5 mm or so) and then pull the end of it out to the side slightly, release the pressure from the front and the end of the strip should become free of a retaining clip.
Do this at both ends and then you should be able to carefully pull the strips out completely. Mind the speaker cloth with the lower one.
After the strips are off, you will find four screws (Torx types IIRC) that keep the glass in place. Optimally have someone to help while removing it (did I mention the glass is heavy?).