How do you take a system from another species?

[An Dagda]

As the title says, I'm trying to take over a system from another hostile race, but after blowing up everything in the system ( and there was no liberate/conquor option in war goals) I can only continue attacking. So, what do?

[Kitten Food]

You cannot unless it is in a wargoal. You have to choose wargoals at the declare war screen. There is no 'adding' war goals later, such as in EU4.

[NikolaiSan]

I'm guessing this is your first Paradox Grand strategy that follows the CK/EU Formula. You make wargoals in the beginning (like cede *planet name here*, or liberate *planet name here*) and after you do well enough in the war, and gain enough warscore, you can collect your wargoals. If your goal was to cede a planet, then when you win, you get that system. That simple

[An Dagda]

Ah, I see. Yes, this is my first Paradox CK/EU game. Sorry for the noobish question :)

I might ask then, how would I acquire the ability to add such a wargoal as to gain the system I want?

[Dark Thoughts]

You set war goals before you declare war.
If you get declared war on then there is a button in the bottom right where you can set your own war goals too.

[Remoria]

You wouldnt the wars already started. But there was a popup when they declared war prompting you to select your wargoals thats when you should have done it

[An Dagda]

I mean before starting a new war (Previous one ended)

[D#]

Either declare war and have them cede their planets if you plan on purging/enslaving, or liberate their planets if you want to set up civs that have ethos that do not conflict with yours as much for later takeover/alliance.

[Dark Thoughts]

There is a truce for 10 years after a war.
And as soon as you hit the "declare war" button you got to chose your war goals first.

[An Dagda]

Thanks for all the replies.

[CT_Marauder]

I would like to add to this question what about the fact you can make and send in an invading force to a planet? Does that allow you to take it over if they win the ground battle?

I found out about this when I needed boarding parties for a Pirate ship that had it's leader on it and was able to take the ship for my own after winning the battle on the ship. So I was wondering if the same worked for planets?

[Dark Thoughts]

It's the only use for troops since you can't actually disable ships outside of scripted events.
You can only do that with planets set as a war goal though.

[CT_Marauder]

thanks for the answer Dark