You need to fulfill the following conditions:-
1)Have a province in a trade company region
2)Have atleast 1 colonist capacity(can be busy does not matter)
3)Have embranced the institution "New World"

Then the option to manage trade company can be found in the estates menu under "administration centrale"


PS:i wish this mod had a discord server, i had the same problem and had to comb through the mod data to find what i was missing

I find this mod to be much superior to MEIOU and Taxes in all aspects except for religious minorities and the estate interactions