Set A Tag Value Using a Button

Hi, I’m pretty new to Ignition and I am looking for a way I could set a tag value from a component using a button.
I have a custom property which call the base tag path and for the component on my page I use this property to bind it to a tag using indirect tag binding. Now I wish I could use a button to take that component value and set it to another tag using indirect binding.

You can use system.tag.write(tagpath, value) to write to another tag. You can get the property in the tree view.

The problem is that my custom Property doesn’t hold the whole tag path just the prefix so I would need to add to it the rest of the tag path and that is what I don’t know how to do I’ve tried many different syntax but can’t find what’s going wrong

If you could post what you have it would help but basically

val = valueToWrite