This new translation by Bhikshu Dharmamitra from Kalavinka Press give three major methods that are not identical. Here are some excerpts from the Introduction to this small (200 pages) book. Nāgārjuna on Mindfulness of the Buddha also contains a Glossary & Bibliography.
In his Treatise on the Ten Grounds, a third of the way through his
discussion of the first bodhisattva ground, Nāgārjuna explains the
“pure land” practice that involves reverential devotion to and invocation
of the name of a particular buddha with the aim of achieving
irreversibility on the bodhisattva path with the option of gaining
rebirth in that buddha’s purified buddha world. It is my translation
of that single-chapter discussion, “The Easy Practice” (Chapter 9)
that constitutes the first section of this book.
Later in that same text, in the final third of his discussion of the
first bodhisattva ground, Nāgārjuna explains in great detail how
to engage in “mindfulness of the Buddhas” practice in such a way
that one may then enter the pratyutpanna samādhi, the samādhi in
which one is able to see the buddhas of the ten directions and listen
to them teach the Dharma. It is my translation of that marvelously
detailed six-chapter discussion of “mindfulness of the Buddhas”
that forms the second section of this book.
Two thirds of the way through the immense (34-fascicle)
“Introduction” to his 100-fascicle Exegesis on the Great Perfection of
Wisdom Sutra, Nāgārjuna presents a very detailed description of
“the eight recollections” of which the initial subsection is his discussion
of “recollection of the Buddha.” It is my translation of that
discussion that forms the third section of this book.