These are the kind of relatively simple jobs that can get you in big trouble. I would suggest having a good body shop or glass shop that you are familiar with do the job. It won’t cost you alot and they have all the tools and materials necessary to do it. That being said you simply slide (pull) the old glass out (glass shops have a tool that clamps on both sides of the glass), clean out the channel, and reinstall the new glass with new insulation that fits in the channel. Hopefully, the division bar (vent window assembly) is still in the car. It is nearly impossbile to do this with the assembly on the workbench. If you are reassembling the car put this assembly back in the car before you do this glass swap.