This tutorial should solve 99% of the league file questions. Please check this first if you are having trouble.

1) Download the league file. You can find it here.

2) Extract the league file. Make sure it is downloaded to the default OOTP5 directory. For example, on my computer, the default directory is:
C:\Program Files\Out of the Park Developments\OOTP5
The folder should be named Talksox.lg and it should be in OOTP5 [OOTP5\Talksox.lg]

3) Load the game. If the league is not there on startup, click file, then open directory and select Talksox.lg

4) If it is not there...then you installed it incorrectly. If you see Career 2003.lg, then check that your TalkSox.lg is in the same folder using Windows Explorer. If you don't have Windows Explorer, you probably have a Mac. I can't help you then, unless you get a Windows Emulator like Virtual P.C. Then return to step 1.