Login/Auth & Redirect URI Help

Ah I think I may have had the wrong syntax when I was trying to key in my URI redirect. I have registered and also replaced areas with the client id as needed but I keep receiving either one of the two following errors;

{“error”:“Bad Request”,“status”:400,“message”:“Missing param: client_id”}
or
{“error”:“Not Found”,“status”:404,“message”:null}

Would I need to create a separate page specifically for redirects?