The official Asus website contains the user manuals for the T100 series of notebooks, as of 2015. The site provides a separate manual for each model of the notebook.
From the main page of the Asus website, click on the Support section and then click on the support search box provided on the page. Type "T100" in the search box. Click on the Manual & Document link next to the correct T100 model, choose the appropriate language, and click on the download link. This either opens the manual in a browser window or initiates a download of the file in PDF format.