Frist thing is get the (TADST) from this link: https://www.armaholic.com/page.php?id=11655 and you need to install Arma 3 tools from Steam Library
Before you go to the second step did you signed you mod or mod that you used is signed? if it no then go to Second step
Second thing is you need to create a key create from Arma 3 tools C:\Program Files (x86)\Steam\steamapps\common\Arma 3 Tools\DSSignFile
List thing is open where you save your key and copy it and place it in your server folder called keys or key
and open TADST and fill it if you don`t know how to use it watch this video:
Go to tap called Rules it Must be like this
and make sure you mod is checked
You Ready to Go!