Don't try ! A master's guidance for Tibetan practices is a "must". Don't try it without a teacher. Don't do it !!! Get a teacher first !!
Empowerment from a teacher (blessing and sending energy into the crown Charkas- the top of the head - Kuan Ding) is always required before any Tibetan practice. It is for the purpose of protection, purification,permission, and guidance from the lineage of masters.
Before any practices, many steps of preparations are always required- so call "Preparation steps" -- such as Mantras for million times, big bowings, etc. Take the steps carefully !
Without the protection, guidance, purification, .......anything might happens, you have to be responsible for it !!
It is not advised to passed down Tibetan methods without the present of a real teacher.