Step one, determine my resources, if starting with just a pick or an axe its more FUN!, however i normally bring along 3 anvils some hour glasses, a pittance of stone and wood enough picks and axes for all of my skeletons, i aim to start with at least 2 ghouls, and at least 2 warlocks, and 2 weapon grade bars (bloodsteel/mithril/steel)
step two. forge weapons for the pair of ghouls (scourges) put them in a milita and begin training / slaughtering wildlife, while everyone else starts up the camp, butchery / tanner / soul syphon / forge / mason / crematorium / corrupted forge / carpenter / blood winery / etheral gate / stonecutter
step three, milita kills wildlife, execute prisoners in chamber for 2 more ghouls put them in milita, (dont meta game and make more because you -can- from two prisoners, cheater) set up a bloodsteel industry ON the surface , build a 1x1 wall, a ramp up and a floor to make a roof for a barracks outside, make 2 sets of leather clothing. make full suits of bloodsteel armor for your 4 milita, try not to have them chase wildlife everywhere all the time
step four make skeletons up to 10 before the first migrant wave make them all pick's (bloodsteel, there is a reason) melt your old picks if not bloodsteel. your goal by autumn is to have 4 ghouls and 5 skeletons (perferably bloodsteel skeletons), ghouls with scourges, skeles with pick's for the first siege / ambush with your warlocks safely tucked away in their bed chambers below the surface, it would be wise to set up a gated doorway to the inner fortress before hand because elves tend to RUSH your meeting hall for some reason.
step five, winter, After cleanup of the first local sacrifice of meat/scalps/souls/bones make a few Dreadnought weaponry for your minions, tap out your bone/ash supply making a bunch of ironbone. make a few anvils, move everything downstairs, res any skeletons that died, laugh at any ghouls that died.
step six spring, Graveyard summons ghouls for meat, its 1 in 20 tries so keep queing it. don't set it to repeat, i tend to keep my ghoul count low, up to you however, multiple graveyards speed this process up tremendously. make Extravagant royal palace rooms for all your warlocks, complete with their own dining rooms. tombs and whatnot, be sure to have a little dorm for the ghouls (each assigned their own bed not just a "dorm") start making some gems from rocks, and upgrading a skele to your master crafter, takes 50 souls and 150 cut gems to give it legendary weapon/armor/metal/blacksmithing/leatherworking/cooking/brewing/engraving/clothier/tanner by next year make another, top them off with dreadnought for grins. remake your milita gear (9 sets of masterwork bloodsteel!) or at the least their weapons, then play with magma if you like. get some to your magma corrupted forges to make it more effortless.
Step seven, once your groundwork is completed your miltia of 9~10 is training constantly do whatever you like, no siege is gonna break it, res the skeletons replace the ghouls ect. if your ghouls are having issues training becuase 2 are elite and 2 are raw recruits, put the elite in the 4 horsemen positions, and make 2 more recruits for a milita, consider making Death a scythe weilding Skeleton, at least ONE horsemen needs to be an archer, for annoying birds...