The way I did it was to supply a ZIP file with the metadata to be installed into your AppData\Daz 3D folder. In there is a RunOnce folder which executes DSA scripts allowing you to process metadata in a queue (the user will get a dialogue box when they open Daz Studio asking them to confirm adding it to the Smart Content). It should be noted that this method also requires a copy of the DSX and DSA in the Runtime\Support folder.
It’s also possible to create a Manifest.dsx file and have it install automatically via the Daz Install Manager. This would require the user to place the file in their DIM downloads folder and install the content through it.
The DSX files are basically XML files, and are simple text documents you can edit. I’ll list the basics here.
<!-- The following line tells Daz that you want to install items into the Content database -->
<!-- Items enclosed within the block are the items you want to install -->
<!-- As with html and XML, you can close a block by using the forward-slash in front of the command -->
<!-- Begin the products block -->
<!-- Name your product and begin the product block -->
<Product VALUE="Marvello's Magical Booties">
<!-- Single line values terminated with a forward slash at the end of the line -->
<!-- Optional Artist name -->
<Artist VALUE="Herald of Fire"/>
<!-- An Asset is an individual object, whether it iss a material preset or figure. -->
<!-- This begins the list of individual assets, each one should be encased in asset tags -->
<!-- The link to the actual file -->
<Asset VALUE ="People/Genesis/Clothes/MMB.duf">
<!-- This line tells Daz to treat the item as a pair of shoes -->
<!-- Audience suitability. -->
<!-- List of the categories you want your item to be listed within in the Smart Content. -->
<!-- Remember, close blocks with a forward slash before command name -->
<!-- This is the closing line for the ContentDBInstall -->
I hope that’s simplified enough to understand the basics.