TO GET THIS TO WORK YOU NEED TO DOWNLOAD IT FIRST AND FOLLOW THE STEPS 

1)UNZIP THE FOLDER FIRST
2)YOU WILL GET A TEXT FILE 
3)DOWNLOAD BANNER PASTE MOD 
4)THEN COPY THE CODE FROM THE txt FILE 
5)OPEN THE GAME AND GO ON THE TAB WERE YOU EDIT THE BANNER 
6)THEN PRESS Ctrl+V
------------------DONE--------------------

https://www.nexusmods.com/mountandblade2bannerlord/mods/1003
MOD:BANNER PASTE 
AUTHOR:gooboon