I know exactly how to do this, the problem is that you are asking questions here that cannot be answered because you're not providing enough info.
"All Online games" => which ones? There's thousands out there...
"Download/upload"=> Which method: FTP? HTTP? BT? Newsservers? Limewire? Again: many, many different ways to upload/download, each having either their own ports (or randomized ports)
"Videostreaing" => Not port-based, so cannot be prioritized by port-based QoS
The only thing that can be done from your info is "Webbrowsing". There's only one port for that (usually): 80 TCP
Thats why i'll make this topic because i don't know what port i'm going to input the QOS ENGINE RULES
Go visit the link I provided, you will find all the ports you need to know/to enter.
But with a friendly note that apparently you're running a business and you absolutely have no clue what it's about. But you can forget about that remark.