how can assign one keyword to search or collect

First I search a name of characters, for example: Concepcion. Second I try to put one keyword: concepcion at the search list, but its impossible, are there any way to complete this task. Many thanks.

You can assign a keyword to multiple documents by selecting them all in the binder (Shift- or Ctrl-click), then dragging and dropping the keyword from the Project Keywords window (Project > Project Keywords) onto the selection. If you want to tag all the search results with the keyword, just click into the binder and use Ctrl+A to Select All, then open the project keywords and drag the keyword onto any of the documents in the binder. You can drag multiple keywords as well.

excelent!, many thanks,