I am confused about these two numbers: wand firing and range attack. I have a mage that decided to learn about archery/scouting - and thus became a necromancer. He has Warlock's Want, which has ranged attack 6. This necromancer has Wand Master level 3 and Marksmanship level 2. How are these two combined together - or are they? Do I have to equip him with a bow and arrows to take advantage of the ranged attack bonuses he gets from Marksmanship?

Does precise shot influence the range damage caused by a wand?

Wand master and Marksmanship aren't combine. Though you can get Initiative bonus.
I liked to use bow/crossbow and sphere of wisdom
Precise shot doesn't work with magic shot (on wand)

Multiclassing ranger, fighter, and mage with each other is generally not recommended (although gremilion can probably make it work) Each of those three classes focuses on a different method of dealing damage to enemies (melee, ranged, and magic); its better to be a master of just the 1 then kinda average in 2.

Stick with a pure class, multi class for the non damage abilities (ex: armor for fighter, spellcasting for mage, diplomacy and the like for ranger), or to multiclass with a commander whose combat abilities are boosting your troops rather then just his own damage (a commander on the field is basically a weak fighter).

As far as ranged vs wand attack goes
Each unit has:
Defense v melee
Defense v ranged
Resistance v magic (aka defense v magic)

Mage wands all have the "magic weapon" trait. A few melee and ranged weapons do as well.
Magic weapons bypass armor but treat the enemy resistance as if it was armor. This can help against some opponents like the ghost who has low resistance but high melee and ranged defense.
A mage's ability to bypass enemy resistance helps him there, as well as wand specific bonuses.

A ranger's or fighter's armor bypassing abilities (from items and from skills) are all rendered useless by such a trait. So it is better to use a regular weapon and cast a spell to turn it into a magic weapon in the rare case its needed.

Note that if a weapon is glowing, ancient, rune encrusted and does some magical things like stealing life from the victim that does NOT make it a magical weapon, it still deals physical damage and benefits from abilities unless it specifically gives the magic strike trait which explicitly states you attack enemy's resistance instead of armor.

While versed in how enemy resistances and anti resistance works I am not entirely sure on other aspects.
Gremlion knows more, he mentioned a sphere of wisdom's extra ammo ability works for a bow if you dual classed.. So, its kinda hit and miss on which abilities stack and which don't, it would probably be easier to ask about a specific ability rather then a comprehensive list

Mage-Fighter is very strong multiclass (better than fighter-mage).
ranger/mage and mage/ranger interesting too. For initiative and mobility. Scout/mage worth getting when you get good early spell which complement diversion. (Like cloud of fear or mass slow).

A mage's ability to bypass enemy resistance works only on spells.

I like sphere of wisdom for experience boost.

That's too bad. This hero has Book of Necron and I was compelled to make him a necromancer.

But why does the wand always have "Ranged attack" as a property, while it should be, apparently, firing. Does this mean that "ranged attack" on a wand is a completely different thing from "ranged attack" from archery? *THIS* is what confuses the hell out of me.

Oh, and if the mage/archer increases the range with Marksmanship Level 3, is that going to increase the range of the wand? Every wand has a "range" property............... but maybe that's again a different "range" from archery "range"?

The OP is talking about the skill called "wand firing", giving bonus to ranged attacks but only the wand ones... and how does this combine (or not) with "bow" ranged attack ...

Yes, more precisely, the fact that a wand has, for instance "Ranged attack 6", and Marksmanship gives a bonus to a hero's ranged attack (let's say, +2), now what is the ranged attack of the wand? I mean, I can see what happens with my hero here, and will post pics, but it doesn't make sense.
Here are three screenshots: the hero with Warlock's Wand has ranged attack 11, with Dwarven Crossbow his ranged attack is 10, and without any ranged weapon it is 0 (as expected).


To make things more confusing, Dwarven Crossbow has Ranged Attack +7 while Warlock's Wand has Ranged Attack +6.





gog.com didn't let me have the other two attachments in the previous post, so here goes the pic of the hero with Dwarven Crossbow.

And finally, hero with no ranged weapon in his hand.

dwarven crossbow (ranged attack 7) + level 3 accuracy/marksmanship/whatever skill (ranged attack +3) = ranged attack 10
This matches your stats.

warlock's rod (wand attack 6) + level 3 wand mastery (wand attack +3) = wand attack 9
Your stats indicate 11 rather than 9. Most likely one or two of the other items you are wearing are giving you an additional +2 wand mastery. (A quick check you can do is just start pulling off your other gear.)

Note that the "bypassing defense" skill for wand is "energy management".

Your hero have gloves with bonus to wand damage,
+6 wand, +3 skill,+2 gloves=11

OK, that makes sense. So for wands, when I read
ranged attack, I should think of wand firing. And when a hero gets a +1 bonus for ranged attack, he is not getting a bonus for wand's ranged attack.

Interestingly, while precise shot doesn't contribute to the wand's ranged attack, the bonuses in ammo that come from Archery levels, do!? So, if you get Archery Level 3, Precise Shot +3 does NOT apply, but Ammo +3 DOES!

so what? Gremlion made a statement in here and I am asking to clarify.
Its not even thread derailment because even though its not 100% exactly what the OP asked it is a VERY closely closely related issue