Go to http://www.osflash.org/red5, scroll down to where it says Project Updates and under that is says Latest Release. Click on the link that says Google Code Page. Scroll down to where it says Latest Official Release and under that it says Installers. The first one listed will be the latest version of Red5...Click on the Windows link and then click Save button.
NOTE: The latest version right now is Red5 0.9.0, and the filename is setup-Red5-0.9.RC2.exe.
NOTE: You can also get the code by going to http://www.red5.org/ click on Releases in the left sidebar and the latest release will be at the top. Click on it, then click on the Windows link, and Save it to your hard drive. (it seems it is better to get the code from the Google page because it is updated more often)
Double click on the setup-Red5-0.9.RC2.exe file on your computer to install Red5.
It will default to installing it to C:\Program Files (x86)\Red5 , but I changed it to C:\Program Files\Red5
When it asks you to Enter an IP Address for your server, type in 127.0.0.1 if installing it locally, or type in the IP address of your server if you are installing it on a server.
When it asks you to Enter a port number for HTTP Requests, type in 5080.
Now Red5 is installed!
START RED5 SERVICE: Open your Control Panel, double click on Administrative Services, double click on Services, then find the Red5 service in the list of services, right-click on it and select Start
TEST THE INSTALLATION: Open a web browser and type in http://localhost:5080 and make sure you get the Red5 test page.
RUN THE DEMOS: Go the the directory where you installed Red5 (C:\Program Files\Red5). Then double click on webapps directory, then double click on installer directory, then double click on installer.swf and you will see a list of demos. Find the demo you want to run, in our case that will be SOSample, click on it and then click the install button, then click "OK".
Now that the demo is installed, go up a directory so that you are in webapps, then double click on the root directory, then double click on demos directory (so you are in C:\Program Files\Red5\webapps\root\demos), then double click on ballcontroll.swf to run the demo. Double click on it again to open a second one. In both windows, click the connect to red5 blue button (the yellow light should turn green). Then drag the ball in either window and it should drag in the second window. This shows that Red5 is installed and working and that communication between swfs is possible through Red5.