hey, you should also open up the "Tech guide". It's located under "utilities" when you go from the start button, then iron cross, then u see the utilities tab, slide over that and u will see 4 utilities. The Iron Cross configuration is where u go to click on the patches button, then u will see how to get the 10 tech slots. oh yeah, if u do not understand Spanish very well, then when you open up the configuration tab, u have to at the botton there, click it to make it show english. On that you cna also set all techs to start in 1933. That helps too cause that way you do not have any negative researching cause ur researching something before you should.
When you open up the tech guide, immediately change the language to english then tell it to "load" then you will see all teh techs for every tech page. just click on a tech and make it green. it will show u some prerequsites (if there are any) in red. You can also click on the "view" button to see what techs you have to research as prerequisites that are listed on other tech pages.
here is an example: to get advanced infantry you need Improved infantry and Basic Machine Gun (this needs Improved SMG and Army Planning) army planing is on the Industrial page and it needs a bunch of other industrial things researched first.
if you want "medium prototypes" you will need to research the following, in this order:
Special materials (needs chemical industry and average industry) chemical industry needs basis industry) and 20mm under light prototypes and to get the 20mm u have to research 12.7mm first.
to get any kind of "Improved airplane" you need to get Production planning, which needs a bunch of stuff like, Ind. Training Inst. which needs tabulating machines, calculators, basic electronics, vacumm tubes. also u need "forced recruitment, military service and census and Public finance. Most of the things you need to research for production planning will reduce your research % so to offset that u want to research as much doctrine as you can and do an many naval ones to boost up your research % or your research will be so slow it wont be funny.
The tech trees in this game are quite intense, but once you get to know them it's not as daunting as it seems to you at first !
Hope this helped you out a bit.
"refined fuel" which needs selective ind. proc., chem industry, boost mining, then u need energy1, rare1, metal1 and oil1 is for naval techs and basic motorized which they will help alot in the begining of the war.