Customising a shed is not at all difficult or time consuming, it just requires the right tools and approach.
The only type that will work in this way is tempered glass because it can support its own weight when used as a single pane without the aid of other materials. You could use laminated glass instead, but again, it would rely on additional strength from the frame or assembly that supports it to prevent breaking. Tempered glass is designed to break into large, blunt chunks that will not shatter into dangerous shards when broken.
Measure the location where your window needs to be cut out of the wall panelling using an accurate tape measure and ensure the opening is 4-5 feet above the floor. Use this measurement on your tempered glass panel (or laminate) and mark a cutting line using a pencil. Also take measurements of the top plate and bottom plate, four corners, two studs (required), the size of the wall, windows, and the frame. The frame width and length should be accurately measured.
If your shed is brand new and no framing or interior wall panels have been installed (there are no existing studs), you only need to trim out the window opening and fit structural wood panelling material. Simply cut the piece of wood you will use as a sill (the bottom edge of your window) first. You can mark this measurement on your tape measure too if it helps keep track.Then, cut out the rest of the opening using that same measurement. Use a file to smooth down the rough edges of the wood sill. This will help prevent wear and tear on your window glass over time or when it is installed.
Next, position, install, and secure the actual window in place using window clips and sealant to hold it securely against the sill you just created. Keep the window straight. Make sure it is clean and dry before you begin putting the window in. You may want to use a small piece of scrap wood underneath each side of the sill to give yourself a better working surface.
Next, seal the open space in the edge of your window glass with clear silicone caulk to prevent water from flowing in through the sides of the window. Over-caulk the window at each side, but don't smooth the excess caulk out. It will be easy to trim it away later with a utility knife. The end result may not be as expected if taken reference of a DIY project.
The stud, header and siding are important when you install a shed. The header should be over the door as leaving a door without a header is dangerous. A bead and stud on the shed adds to the strength. Siding can be added to the edges of the shed.
Hammer.
Nails .
Screws.
Good quality timber.
Paint.
In truth, it depends on the type of shed you have and what kind of window you are putting in it. A panelled shed with windows already installed will be considerably easier to install into than a brand new shed with no interior structure. A good guide is to allow a few hours for installation if your window does not require any cutting or drilling. Use a circular saw if the opening design is circular.