My windows open inward and up, I have a screw eye in the wall and hook on the window frame that goes in the eye to keep them open. I use two hinges on the 22 inch wide x 56 inch deep windows on the home made frames. A table saw makes quick work of building frames.
Here in Michigan I learned quick sliding windows freeze shut during snow and ice storms. Folding them down I kept banging them and folding them out collected snow and ice that came in side when shutting them.
Al