How to activate "Services"

I am new to using contectual menus.  However, the items for DT are dimmed.  I am trying to import as text from Safari with DT running. The menu sequence is Safari/Services/DEVONThink/.,  the dimmed choices are Lookup, Summarize, Take plain note, Take rich note.
Why are these dimmed?

Probably because there’s no selection available - just select some text of a page and the commands should be ready to go.