Click on your Steam Workshop button in the search bar look for "Trader"

Then we need to select Install, this will automaticly add the Trader ID to your server startup:

Next we need to confirm it has been added to your startup commands in your configuration files section click on the Easy Configuration Editor button of your Workshop.mods file
if you are using the new (one click update all mods) system it should look like this:

(*NEW SERVER OWNERS IGNORE THIS IMAGE*)
if you are using the "classic workshop installer" you need to add the trader mod to your workshop.mod configuration file manually:

CONTINUED:
the next stage is we need to copy the @trader / @1590841260 config files to the server profiles folder
in your filemanager navigate to your either @trader OR @1590841260 folder inside here you will find a folder named "serverprofilefolder" inside this folder is a folder called "Trader"
we need to move this folder to your root SC folder as shown below our newest template this is called "profiles":
from @1590841260\serverprofilefolder\trader\ to sc\trader\

once this has been completed it is safe to start the server, you can confirm your server has loaded correctly by checking your dzsalauncher link Guide here
https://dayzsalauncher.com/#/servercheck/