Firstly, here's a page you might find useful..
http://home.swipnet.se/~w-96979/games/wow.htm
The basics...
You have the two main screens.. The War Room and the Battle (sector) Map.
To build structures and defences, move units and attack targets you need to be on the Battle Map.
Moving Units to other sectors, producing vehicles in factories, research and the like are done from the war room.
You have several views of the map in the war room...
The basic one that shows (by colour) which side has the sector (Red is enemy, Green is friendly.. the greener it is the more units and defences you have in place and so on.
The Resource View that shows what mining facilities you have and production maintained and Construction View.. Where you can build your vehicles and so on with the factories you have built. Right clicking on a factory gives the units that are available to build and so on.
On the Battle Map, right clicking on a unit gives you options (ie. move, attack, roam, etc) for orders you can give that unit.
Research will enable you to build bigger and improved units and some new weaponry.
For some Units, once researched, you will need to build additional structures, apart from the factory, before you can produce them. For example.. A Submersible, in order to be built will require that there is a Laboratory as well as a Ship Yard in the sector.
You will need to keep an eye on resources and build Mining facilties accordingly or your production will slow right down.
In order to take and hold a sector you will need to either..
Move into a vacant sector with a Construction machine and Build a Command Post.. or..
Attack an enemy sector and destroy their command post. Then you will need to build a command post for this sector,
Either way.. you must have one of your own command posts built in a sector before you can go through it.
Sapper Lorrys build your defences.. Defences are essential.
If in doubt holding the cursor over anything for a few seconds will tell you what it is and some stats etc.
That's the basics.. anything else you want to know?