How do you assign ships to Naval Invasions?

[CenturionsofRome]

Instructions are extremely unclear. I have gone through every tab I can find, including setting task forces in the area to "invade" stance, and I've never found a way to assign ships to the invasion like the instructions in the patch notes says, or gotten a single invasion to succeed, even when the enemy has no ships in the area.

[admiralsnackbar]

This is how [i think] i did it

1. Have a task force of at least 100k tons total displacement on 'invade' with the command radius in range of the port you wish to invade
2. Go to politics and select the country you are invading, the naval invasion button should be clickable
3. Select port you wish to invade 
4. Keep the ships in range for a few turns