In DDSCF21 the game will automatically generate a linked.json file in your Documents\Wolverine Studios\DDSCF21\Leagues\YourLeague folder when you save the game.

In DDSPF21 you can go into options and link a league by browsing to this file. Every time you open your league from that point forward will load the latest version of the linked.json file. 

If you want to have more control over your linked data, then every time you save your DDSCF league you may want to make a copy of the linked file with a different name and use that in DDSPF instead.