The Guild Dungeon is pretty straightforward. You fight battles against
teams of Heroes or teams of Titans. This process repeats over and
over with different opponents. The battles in the beginning are pretty
easy but they get harder as you go deeper into the Dungeon. For every
battle you win against Heroes you get 1 Titanite and 25 Titan Potions.
If you defeat a team of Titans you get a Titan soul stone and 5
Titanite. This reward is doubled for all levels you have not done
before. If the guild as a whole collects a certain amount of Titanite
in one day, every guildmember gets from 1 to 5 (really 1 to 15 -- see update below) summoning spheres.
I will admit that I do not go to the Dungeon as often as I should. At
my current Dungeon level it is rather boring, but it helps me and the
guild both, so I should make the effort to go to the Dungeon more
regularly. I hope you do too.
Update: We as a whole have been collecting 4 summoning spheres per
day very regularly and have collected 5 several times. We have
collected close to the 7500 titanite needed for 5 spheres quite often.
This means that if we all do our parts, 5 spheres (the maximum) is
possible every day. By the way, the sphere numbers are cumulative so
that if we get those 5 spheres we get all the others too. 1+2+3+4+5.
That is 15 summoning spheres in one day! So what is required from each
guild member on average? Well, with 30 guildmembers that means 250
titanite from each as an average -- some will be less and some will be
more, after all we are not all the same. If you have Valkyrie's Favour
($1.89 US per week) you can get 150 with one click which only leaves
100 to collect manually. Not bad, eh?