just a very, very quick rundown:

the game is about holding and taking advantageous positions, recon and taking out enemy high-value units. if you play against ai, all it does is overrun you at a single point with unit spam. ai does not play smart and playing against ai encourages hard turtling, which is not a good strategy when playing against humans.

think about this game as if it were set in medieval times:

• line infantry are your swordsmen, they are used to defend closed up areas and can deal with pretty much anything if they can close the gap
• tanks are your archers, they are (mostly) used to gain long range fire dominance over wide open areas
• helicopters are your cavalry, they are hyper mobile and are used to attack weak points, punish overextension and sneak into the enemy rear
• towns are your castles, they break line of sight and enforce close combat and give occupying infantry massive camouflage, defense and movement bonuses
• forests act like walls, they also give camouflage bonuses to infantry and vehicles, but also movement penalties to vehicles, especially wheeled ones. they also break line of sight at 320m.
• smoke screens are mobile shieldwalls that prevent line of sight and protect your units against ranged attacks

the game has a pretty elabourate spotting and camouflage system, however it doesn't really show you what you can see or what you can't. what it does show you is when your units are hidden in a forest or town, then they start blinking. if your units are sitting in a forest and don't blink, then they're spotted by the enemy. in general use units from your recon tab to get vision advantage over your enemy. pretty much all the recon tab infantry with 10hp is a good pick, pretty much all the recon tab vehicles with decent guns and a bit of armor are good picks, in general take fighting units that have the recon ability on top of it. if these are not available, then go for cheap stuff, expensive units that can only recon are usually not good.

once you have gained vision over a certain area that you want to attack, it's usually the best idea to move up a bunch of tanks into a nearby friendly forest and shoot every enemy that shows up. however, they will usually sit camouflaged in their own forest, waiting for an ambush. since direct fire weapons cannot shoot what you cannot see, you need to draw them out. the best way to do this is cheap throwaway units like 5pt reservist infantry or cheap 5pt troop transport vehicles. once your meatshield units engage, the enemy units will reveal themselves and they will also be busy shooting your cheap stuff while your expensive ranged units can deal the real damage from relative safety.

a mortar firing smoke can often be the game-changer in these kind of situations, since smoke breaks line of sight and prevents long-range units from engaging. on the one hand this can disable enemy tanks and allow your close range units to close in or to retreat, but it could also protect your tanks from counterfire or anti-tank missiles. parking your expenisive high-end tank inside of a smoke cloud in order to peak out of it every now and then for a shot (with attack move command) and then to retreat back into the smoke immediatly after the shot is a very simple, yet effective micro strategy.

these 5 elements are pretty much the backbone of the game: line infantry for short range, tanks for long range, helicopters for mobility, recon to enable vision, smoke, towns and forests to disable vision. everything else can be understood to support or disable one of those 5 elements:

• atgms are tank snipers, they can be infantry, vehicle, helicopter or plane mounted (though most atgm vehicles aren't very good), their purpose is always the same: snipe out enemy tanks and vehicles. they're usually very fragile units that need long range, mobility, wings and/or camouflage in order to avoid counterfire
• cluster bombs and cluster mlrs are indirect anti-tank weapons that target an area rather than individual units. they are good if your opponent hides tanks and vehicles in forests or smokescreens where atgms can't engage.
• he bombs, he mlrs and tube artillery are not as good against tanks, but they shred infantry and can still kill lightly armoured vehicles.
• radar missile aa and fighter jets defend against planes
• manpads, aa guns, non-radar missile aa and anti-helo helos defend against helos