The BNet guides are extremely outdated, so don't use those.
Here's a tactic that's good for learners in solo, CL+DK fiend+statue+wyrm, this is better for starters because fiends are easier to micro than ghouls, and it's a pretty versatile strategy that, when you have more practice, can transform into dk+lich+cl fiends+stats+destroyers.
Ok, so here's the Build Order:
Acos to mine, ghoul to wood
Queue 1 aco
Pick an aco and build a graveyard and a crypt
Queue 1 aco
At 150 gold build a zig
At 180 gold build an altar
When Crypt is done queue 1 ghoul for lumber
At 215 gold queue 1 crypt fiend
At 150 gold build a ziggurat
When Altar is done queue the Crypt Lord
At 215 gold queue another crypt fiend
Upgrade your first ziggurat to a nerubian tower, useful against harass
At 120 gold queue 1 more ghoul for lumber
When Crypt Lord comes out learn carrion beetles, use it near the graveyard until you have like 3 or more beetles
Build a Tomb of Relics
Upgrade to Halls of the Dead
So you start creeping with CL, 2 fiends and 3+ beetles
During the tech you get some more fiends and 1 ziggurat
When you reach tier 2 immediately get a DK, slaughterhouse and web, in that order (research and use burrow when you have better micro)
After that tech to Black Citadel
During this tech get a sacrificial pit and 2 or 3 statues (1 or 2 for healing, other for mana)
When you get to tier 3 build a boneyard and start pumping frost wyrms
This should get you started pretty quickly.
Recommended skill order for CL: Beetles-Carapace-Beetles-Carapace-Beetles-Locust Swarm-Whatever
for DK:
Coil-Unholy Aura-Coil-DeathPact-Coil-UnholyAura-UnholyAura-Whatever
The reason you don't get animate dead is because you are using the corpses for beetles and skeletons. Remember to death pact the beetles when your DK is low on health.
Hope this helped.