That depends. The old ones created each type of lizardman/Seraphon with a specific intention in mind.
If I an a skink, what do I do? From there it depends on spawning. If I spawned alone, I might be a castor or chief, interpreting messages of slann. If a regular spawning, I’d probably be an artisan, maybe even overseeing or planning on construction of buildings to he built by Kroxigors. Certain skinks can learn to cast spells.
Saurus are the more militaristic ones. They’ll usually be in garrison or on guard, outside of that I’m not sure what they do. I’m not sure what different soawnings mean, but I’m pretty sure if a Saurus spawns in small groups or by itself, it or they are seen as destined fir greatness (probably in combat/leadership role on battlefield).
Kroxigors are the laborers. Not many are thinkers. In battle, they can be seen wielding construction equipment. Not sure what different spawnings mean for them.
Slann are essentially the brains. They have insane reserves of magic and interpret the will of the Old Ones, though they are struggling to interpret the great plan after the old ones have fled.