Thrangu Rinpoche has given several teachings on Vajrayogini practice which is a higher level practice and one should have received at least the reading transmission of this practice from a qualified teacher to actually practice it.

This PDF of over 40 pages contains and explanation of the practice and the concepts involved with doing the practice.

This website also has a good explanation of the this practice for a slightly different viewpoint by Khenpo Tsultrim who  taught with Thrangu Rinpoche for several years.

This website also has a PDF of  Elizabeth English's book which has a 500 page explanation on all aspects of Vajrayogini practice.