HEMAN: until the help file is put together (which I foolishly offered to help with

) you'll need to go into the
Components text file (in Data folder) and search for what various technologies will allow you to build (use the search function).
Sometimes it's difficult to figure out what technology prerequisites are needed for further research, and so in that case you'll need to crawl about the underbelly of the
TechArea text file.
Hope that helps.