AoS New player starting out a narrative campaign

[Milou]

Picked up a on sprue pile of shame and a seraphon army box as well as hunters, besides that I can also borrow my friends unused seraphon army. Was looking to start a narrative campaign with a group of friends (with some altered rules, allowing me to change between constellations).

Models I have access to

1 Lord Kroak
2 Slann
30 Saurus warriors
34 Skinks
10 Hunters of Huanchi
3 Terradon riders
3 Terrawings
5 (old) Saurus knights
1 Oldblood on cold one
5 Raptadon Hunters
5 Raptadon Chargers
1 Bastiladon Ark of Sotek
1 Bastiladon Solar Engine
2 Stegadons with Skystreak bows
1 Stegadon with Engine of the Gods
1 Carnosaur with Oldblood
1 Troglodon
1 set of Starblood Stalkers
1 Unbuilt Carno/Trog

I've played a couple games of normal AoS (1000 and 2000 points) with Koatls Claw and then Thunder Lizards. At the time I just played the models that were available to test out the faction, now I have the opposite problem of having far too many choices and no experience in army building.

We're starting out with just 600 points and I have no idea how to go about it (note can proxy models as others since we're just playing with friends ie: Klaq-Tor as an oldblood on foot.

Any suggestions would be very welcome!