[How I create a Transfer Window for a nation]

Hi, I'm adding some new playable nations and I didn't find by any means the transfer window area, to allow me to create a transfer window for those new playable countries

 

[Can someone help me to create a two divisions with decisive playoffs?]

I want to make a Nation Playable with two divisions (both with 10 teams) but I want to create the following system.

The 2nd Division:

1st Normal League stage

2nd Title Decider Playoff between the top 3 teams

3rd The winner will be rewarded with automatic promotion and the losers will play a Relegation Playoff with the 8th and the 9th of the superior league.

The First Division:

1st Normal League stage

2nd Last Place will be automatically relegated

3rd Title Decider Playoff between the top 2 teams

4th Will have a Relegation Playoff between the two teams who lost the Title Decider from the Division below and the 8th and 9th place.

 

I don't know how advanced rules work, so I would like a good explanation to help me make this Nation Playable.

[Error in Nation Rules]

I don't have any clue why the editor (hates me) is saying this error. What are the parts I need to print to get some help there?