[Mr. Marlin]

It's all about file naming. The names have to match the team and the year (if you want them to progress with time). Also historical logos are "mostly" all there in the base game. The Indians are gone but that horse has been beaten to death. Historical uniforms are not included in the base game but you'll have no trouble finding them here.

For the logos to work the file name must be:

new_york_yankees_ (starting date)-(ending date)_color hex code 1_color hex code 2.png

Caps naming is:

caps_new_york_yankees_starting date-ending date_home/away.png

Jerseys are the same except the file name starts with jerseys. Once you have the caps and jerseys just paste them into the appropriate directory in you game file. It's pretty self intuitive once you see it.

It makes no difference if the game is fictional or historical or modern. All that matters is file names