This is a bit clearer here
Delete your old client.
Download the updated client
Get a fight id from a url, ex http://www.onlineboxing.net/scorecard/846202. The last number in the URL is the id
Open up a command prompt & enter "cd C:\Users\Desktop\boxing\client-zip" (make sure you copy it from the folder and not this post)
Next you type "run.bat 846202" (or whatever the id is) and the fight will show