Spawn creature

You have to add the coding for each dino within the engine settings on your web interface. It will be at the very bottom in custom game ini settings.

Or you can go into expert mode and add it that way. Once you're inside expert mode you have to remain in expert mode though.

also be warned some dinos do not work and can cause the server to crash (mainly reapers)

Also in case you ask for the creature code/info.

Creatures - Official ARK: Survival Evolved Wiki

And you will need to know every spawn point on each map you try to run.

Are you looking to just spawn them in using admin commands or are you looking for them to spawn in naturally like the normal dinos?

Then you would add them how I said above. If you search the forums for ini code you will find a lot of examples on how do add them in. You just need to change each coding for the specific dino and location as DOAGEN said.