First you gotta enter on Steam then select community workshop and after that select CS2 then search crashz's viewmodel and boom click subcribe and you will get the map after that load the map you can also change your fov in commands but it's hard BUT if you are curious how check this video :

After you load the map click some buttons that you see on the wall and you will see how your viewmodel is changing based on buttons it's hard to explain but you will figure it out!