Hey, we do have an ingame wiki planned, and if everything works out, it will actually use GPT, to make the usage even more versitile!

To answer a few questions though:
pops provide boost to your economy. But we are actively looking into changing their mechanics, to make them more interesting.
When selecting a pop to man a ship, you usually just pick the "worst" one (you can check values of a pop, by hovering your mouse over him/her)

On a new coreworld, it depends a lot on the tile bonuses. If you see research bonus tiles, go for research buildings, if it's manufacturing, go for manufacturing, and so on.

Hope this helps!

This is a relatively balanced planet, but still with good possibilities for manufacturing.
I would start with 2 factories, shipyard, one research building close to you capital in that bonus tile, and then continue focus on manufacturing, with a few exceptions around bonus tiles

I usually build a balance of districts. Factories, Labs, and Economy. Looking at your inputs you will get a lot of farming output if you build some farming districts, and a significant amount of money if you build some economy districts. Mineral and technological input is low so you wouldn't expect to get much of either manufacturing or research even if you build a lot of districts.

Colonial generators and supply depots don't produce any pollution, so I would consider building those at the very least.

Before I forget, supernova is under developments and may change a lot in coming updates. The next update is expected to break saves.

I'm not an expert on trade routes. I'm a war monger so I prefer warships over trade ships. That said, I do read the forums and discord, so I should know a few things.

You can set up a trade route by sending a freighter to another planet. Kinda like colonizing a planet. Once established, a trade route will be setup between the planet that built the freighter and the planet the freighter arrived at.

Only 1 trade route can exist between 2 planets. If the planet builds another freighter, it'll have to go somewhere else.

You can't form trade routes between 2 of your own planets. The destination must be with another civilization.

Freighters can be destroyed if they haven't formed a trade route. I don't recommend sending them to hostile space. Once a trade route is formed, it can only be broken by war.

You don't need permission to set up a trade route. If the other civ is at war with you, you can't establish a trade route.

There are several things that improve the income from trade routes: the distance, age, and income of the two connected worlds.

Trade route improve relations with other civs. Trade routes are profitable for both parties.

You can get more trade route licenses if you turn citizens into traders. 1 license per trader.