I have tried heroes 3 and did the easiest campaign having a hero with lots of troeeps 70 archers 40 marksmen 7 crusaders 22 royal grophons and 6 the upgraded monks lvl 6 cause i cant any higher taking over castles. monsters on the map run away but the more towns you got the more spread out you are for enemy attacks since the computer spawns a lot of heroes and the hard discision do you get troops to defend your city or do you fill your main army but when you do that the city gets weaker to attack so at the end you retake the town but its my question is it better to have 1 or 2 towns to have and easier manageble or is having so many towns good for income?

It depends on many factors. If your goal is to defeat all enemies, you have to attack, whether you want or not. If you have time limit, you even have to act fast.
Also it is good to find and defend some bottlenecks on the map with several heroes and send them reinforcements from the towns with a few other heroes. Also expert earth agic with Town Gate spell helps a lot, if you can have it.

its the mission you have to take over a specific town but since i dont know where it is i take over most towns so i dont yhave to travel far to treinforce in case of a strong enemy hero

You should be upgrading your archers to marksmen straight away to improve damage potential. Don't bother with monks if it means losing out on griffin numbers, unless you have plenty of gold just buy the griffins.

yeah i noticed that on if you attack a town ranged units are the best since it takes too long for a wall to breach i did monks because mostly the cpu attacks the dstance units first since marksmen are great if they are in numbers so the computer will go for the mons first.

Well if you've got the spare resources...the problem is you use up rares to build\upgrade the monk dwelling, as well as them not being that great for the unit cost.

true hadnt think of that thanks maybe i use too much expansive units that i dont want them to e hit by arrows or other distance weapon/magic i think i should use the cheap units a lot as well

Air Shield spell should reduce ranged damage taken. Also Stoneskin will help too.

my hero was a knight i dont know if in heroes warriors can use magic i know you can buy a book at town.

Without Wisdom skill you can learn spells from first and second level Magic Guild. For 3rd, 4th and 5th levels you need basic, advanced and expert Wisdom respectively.

thanks for the reply btw another question can you have any unit in your grp or do have some low moral if they are in the same grp? like getting a demon with arch angel

I think that units from two towns don't make any penalties, only 3 and more. For example with 5 Castle units with Cyclops and Centaur Captain, your army will have -1 morale . Only undead units lower morale for every other non-Necropolis units and they are unaffected by morale themselves.

does that mean that a unit you find on the map has a bigger chance joining your army if that unit is from your army?

No, it does not.

Something to keep in mind with regards to strategy is that the computer tends to create a lot of "nuisance" heroes- basically weak heroes with almost no armies that it simply sends around to grab your mines. Using your main offensive hero to chase these heroes down is a waste of that hero's movement. Instead, have a few secondary heroes with fairly weak armies (but strong enough to take out nuisance heroes) that are used to defend your territory against incursion by nuisance heroes. Also create a few nuisance heroes of your own and use them to scout around and grab unguarded resources and mines, so that your main hero can spend his movement just going to where serious battles need to be fought, rather than doing scouting that other weaker heroes can handle just as easily.

The chance that a neutral stack will join your army is a set property of the stack that's defined when the map is made (this chance ranges from "always joins" to "never joins" and everything in between). The in between chances can be modified a bit if your hero has the Diplomacy skill, but as far as I know that's the only thing that can affect the chance of a neutral army joining.