1. If you look carefully, you will notice lines with arrows leading to tech, which have prerequisites.
Main "opening" techs are Materials, Production Planning, Advanced pieces, Army Specialization, Refining.
For example, Materials "opens" Infantry IV tech
Refining opens Tanks II tech. Just try to follow those arrows.
Main "opening" techs are Materials, Production Planning, Advanced pieces, Army Specialization, Refining.
For example, Materials "opens" Infantry IV tech
Refining opens Tanks II tech. Just try to follow those arrows.