Window glazing is done on single pane windows, generally these are found in older houses. The putty glazing can last for decades, but it eventually dries and cracks and then needs replacing or repair.
This window is a single pane and is covered by an aluminum storm window. The first step is to remove the storm window so you have access to the single pane window.
Notice there is no putty or anything to hold the glass in. Repair needed!
These are glazing points that will hold the window glass, put these in before putting the putty in.
Putty and points - two major supplies for the job.
The glazing point is pushed into the wood frame with a putty knife and then the putty is spread over it.
Now for the fun part. Take a small amount of the putty and roll it with your hands into a "rope" and lay it on the wood. Then use the putty knife to smooth it out like in the photo.
The finished job. Well, almost finished. When the putty dries, you need to paint over it. Also, the wood needs to be scraped and repainted. 1/2 hour = one window. Your skills improve with each window!
Update showing the final product. The top needed reputtying, paint scraping, priming, and repainting. The bottom shows all the improvements. Voila!