Download file and open from webviewer

i used download item to download a file from a webviewer link. It works but in this way I only can download file. If i want that after the download the file automatically opens?
To be precise I need to download an apk file and after I want that this file opens (so starts the installation).
Possible? Any ideas?

use activity starter launch a file


thanks, can you be more precise?

with this block i can download the file. Then how to open it after downloaded?

See here: