The blog Saints Will Arise has extensive notes about praying and chanting the Benedictine Office.
GregoBase has chant scores from many sources notated and typeset and searchable along with scans of their sources. Use it to examine different versions of a score, to obtain the GABC notation of a score for further typesetting, or to get a reasonable rendering of a score for immediate use.
GregoBase: A database of Gregorian scores
The Gregorio project develops free and open source tools for typesetting Gregorian chant.
The monks of Abbaye Sainte-Madeleine du Barroux chant the Benedictine office and have recordings of Lauds through Compline for nearly every day. Their singing is lovely. If you want to hear something specific, get some of their past ordines, locate what you want, and download it from the chant-recordings website.
Chant recordings from Le Barroux
A Bash script I wrote to download the recordings
The Internet Archive has scans of several important chant books:
The Liber Usualis (in English) (1961)
The introduction to the English-language Liber Usualis explains for the novice the Solesmes interpretation of Gregorian chant and related matters like the Italianate Ecclesiastical pronunciation of Latin.