Lumion node replacement

Hey there,
I am not having any luck turning nodes in Lumion into plants.
I am pretty new to Lumion so am having to figure out the program at the same time.
I started in LandFX, imported into SketchUP 2021, converted my plants into nodes and imported into Lumion via live sync. When I select a plant node I can’t get the replace node window to open. It only opens when I have the entire design highlighted. And if I then select the change node option, the whole design turns into 1 tree.
Thanks for your help

Import trees into a separate file