Replacement of broken shoes for double hung (bottom window) with spiral balanced

This is a small bathroom metal window. Both shoes need to be replaced. The bar that fits into the shoe doesn?t have a screw attaching it to the bottom window. so I need the screw. The screw has a square tool fitting in its head. There is a piece of metal in the picture that I don?t know it?s purpose. The right hand shoe is still in the window, but the little wheel that holds the bar attached to the window has come out. I?ll also need the spiral tensioning tool. I?ve just moved into this house so I have no experience with this type of window but it doesn?t look complicated. I saw on one of your you tube videos how to cut a vinyl window to fit the shoe into its slot. I haven?t pulled apart this window enough to see if has easy access for a replacement shoe.