Hard subbing
This is the fun and involving part, though not that tough to execute. I use VirtualDub; you can get it here. It's probably the best AVI tool available. Install VirtualDub with all the plugin options; you are required to do this in the option provided while installation wizard. The main file we will need is actually from VobSub installation, namely called text sub, and it shows up as an option while running the wizard.
Once this is done, it's very easy. All you need is the sub file (placed in a folder you can remember). Then open VirtualDub, get in your video, go to filter (Ctrl+F), and add the text sub-filter. The plugin will open and ask for the subtitle file (.srt), so browse and locate it. That’s all. Preview once and render. It could take a while.
Conclusion
There are other means, but they are lengthier and require more plugins and steps. This gets the job done, and is practical. So, to sum up, you need to either download the files from the net, or create your own, then it’s up to you whether you want to hard sub or soft sub. Last but not least, do respect the developers of the software!
my hobby is multimedia. 
