How to set up Boii Colonies?

[Nightsh4de]

Every single turn I get the advisor popping up telling me I have colonists ready to dispatch. Streuinta my capital is a confederacy and presents no options to create a colony there, the next town over is a protectorate with plenty culture and size 2k (exactly) but I get no option for building a colony, though I upgraded the settlement size. I must be missing something important here, anyone understand colony mechanics?

[QuintusSertorius]

You can only build Boii colonies in places which have a Migration government. Which is not your heartlands.

[Nightsh4de]

Which is not your heartlands.

Thanks Quintus