Sure! You can use a few different Expressions, but the basics are relatively similar.
For solids, the mapping is automatic, so you can apply Templater to a solid and then directly input the hex code you’d like to use in the data source. For other layers, the process is a bit more complex. First, you’ll want to create a text layer with the Templater Effect applied and map it to your data source. For the purposes of this example, we’ll call that layer “color” (with no quotes).
Next, you’ll want to add the “Fill” effect to the layer whose color you want to change. Finally, you’ll want alt/option click the “Color” value of the “Fill” effect and add this expression:
This should change the value of the “Fill” effect to the hex code brought into the “color” text layer.
Hopefully, that’s enough to get you started, but if you have any issues or additional questions, feel free to let us know.