How to upload files to firebase storage using REST API

I am developing a WebGL project. For this, I need to store some images in firebase storage. But I don’t know how to upload files to firebase storage Using rest API. Can anyone show me how to do it? Or please provide me with a good example.

I am developing an app in unity that uses both firebase Auth and a real-time database and firebase storage. On the signup page, I could sign up and upload data to the real-time database using RestApi successfully. I used “RestClient” for this. But when I tried to upload the image to the firebase storage it failed. And return an error. below is the code can anyone please tell me what is wrong with this and how to fix it?

private void SignUpUser(string email, string username, string password, string age_, string mobile_, string instagram_handle_, string City_Of_Residence_, string nationality_)
        string userData = "{\"email\":\"" + email + "\",\"password\":\"" + password + "\",\"returnSecureToken\":true}";
        RestClient.Post<SignResponse>("" + AuthKey, userData).Then(
            response =>
                idToken = response.idToken;
                localId = response.localId;
                playerName = username;
                age = age_;
                mobile = mobile_;
                instagram_handle = instagram_handle_;
                City_Of_Residence = City_Of_Residence_;
                nationality = nationality_;

                     response =>
                        Debug.Log("Image upload error: "+ error);
                print("Data uploaded");
            }).Catch(error =>