here you can download the Modding SDK for TE4 : https://www.managames.com/download.php? ... SDK_v1.zip . (last update : May 2022)
It works like the one for TEM2, except you should use the TE4 Mods folder instead of the TEM2 Mods folder..!

So read all the explanations here : topic11-31376.php .
1 important note though : for TE4, the menu files in "Menu/ScriptTe" are used instead of the ones with the same name in "Menu/Script". TEM2 completely ignores "Menu/ScriptTe" and uses only "Menu/Script".
The outfits are in a separate SDK, to avoid to have to download a too big file when there are some changes in the base SDK.

The animations have their own SDK.

Extra notes :
- the sounds still use the legacy TE2013 Modding ; it'll change in the future, at the very least for the Grunts so they'll require to only be copied in the correct folder without touching any .ini files. It should be easy to convert existing Grunt & Sound Mods to that new system when it'll come. (EDIT: Done, explanations => topic60-33725.php )
- the 2D court modding will have a small rehaul, to make it easier to change the surface physics for many courts at the same time, as well as define different 2D courts for the same tournaments (ie: small court, main court, day/night session) ; the courts should still work without changes after that rehaul ; (EDIT: Done for the new way to add 2D courts, explanations => topic60-33904.php )
- it's not possible to Mod the 3D models ; ie: the players, the 3D stadiums, the NPCs, etc.
- it's not possible to Mod the 3D stadium textures ; it'll be possible to Mod the court surface at some point, though
- I'll try to do a clearer Modding FAQ once the game will be done & its Modding stabilized ; for now, you have to go through the older TE2013 Modding documentation to get some of the basis and thus it can be daunting

- If you have any issues, or before releasing your Mod to the public, look for "error" and "warning" in Settings -> Profiles -> Show Engine Log (on the bottom left), and try to fix them all