Go through the gate you would go through to get to other areas of the digital world (Login Mountain and the like) the Coliseum should be to the left of Shine/Darkmoon City.
You need to find an Armour Digi-egg first, they can be found in various places around the digital world. Then, once you have an Armour Digi-Egg, go to your tamer home, and go on the digi-lab PC. Select Special digivolve, and select the digimon you want to armour digivolve, only certain digimon can armour digivolve, (Gatomon/Tailmon, Veemon, Patamon, Hawkmon, Armadillomon) if they've met the corect requirements, they should be able to armour digivolve.
A2:
It's somewhat like DNA and normal digivolving mixed, where you use the power of a Digi-Egg to create special forms (still waiting to get an egg for my Veemon). The basic idea is that Gatomon and all the non-Gotsumon/Monodramon rookies from Login Mountain (E.G. Armadillomon, Hawkmon, Patamon, Veemon) are the only ones to armor digivolve.
Solarmons are found in Proxy island and clockmon can be found deep in the Chaos Brain
A2:
Solarmon are on Proxy Island (Second to last storyline dungeon I think) and Clockmon are the Chaos Brain (last storyline dungeon, no Transfield doesn't count), though I don't see why you'd want Clockmon.
Q:I am doing a quest and I must kill marinedevimon But I cant its very hard.Can someone tell me what to do to beat him?My 6 digimons is Firamon33lvl,Garurumon28lvl,Ankylomon32lvl,Growlmon25lvl,Seadramon31lvl and ExVeemon20lvl.
A1:
Simple. just train more or cancel the quest
A2:
You need to digivolve to ultimates to kill him because he is an ultimate.
A3:
I kill it with... airdraman lvl 40 flaremon lvl 40 and angemon lvl 45
train harder.....
I really don't think you can get any of the Kowloon Co members, they're special (E.G. No WaruSeadramon, Gaiomon, Spinomon, Grandracmon, whatever Dusk's group is).
A2:
Yes at the beginning of dawn you choose the pack waru seadramon comes in.p.s A1 musn't have dawn