The simplest way to add a new child asset to an existing one is to open the diagram page for the parent asset.

If the asset doesn't have a relationship of the type you're looking for…

• Click Show All (at the end of the list of relationships)
• Choose the relationship you want to add from the drop-down list that appears

Then…

• Press the '+' button to the right of the asset.
• Start entering the name of the asset.
• If the asset already exists, choose it from the list to have it automatcally added.
• If the asset doesn't already exist, push Create to build it.

And your asset is now attached.