I need some help getting started with making my own builds. Any sites around I can use as reference for coding?

I've been to many sites on the Internet that advertise IPTV boxes with all kinds of features, etc, etc. I am absolutely new to this. I have a ROKU stick but I don't really see much for that other than the usual pay subscription services. Any suggestions on where to start with regard to...

Just joined to learn about streaming TV. Looks like there is a lot to learn. Thanks for all the information on the site.