How to reinstall these kind of sash?

Thanks for posting. It appears your window's pivot bars have snapped. The pivot bars are the die-cast pins at the bottom of the window sash, or the movable part with the glass, that connect to the pivot shoes and balance system inside the window tracks. To see if we can replace these for you, we will need to see a pivot bar out of the window, preferably undamaged. If you could measure the distance between the mounting holes and the tip that fits into the shoe, that also would be helpful. You might also determine during removal and replacement that other parts are damaged. If so, let us know. For removal and replacement of the pivot bar, see the video below.

Thanks for getting back to me! I'm having a little trouble reading the measuring tape in your photo, but this certainly does look like the 26-415; moreover, your pivot bar looks like ones we have specifically recommended the 26-415 as a replacement for in the past. So long as the distance from the mounting holes to the tip that fits into the pivot shoe align, you should be good to go.