As Rinpoche advises, we should always generate good merits while having positive thoughts and good intentions. Doing so will help us in our future spiritual practice ; by encountering fewer obstacles and having more freedom to practice Dharma.
One of the way to accumulate merits is by doing Mahayana practice, where we start with the prayers of 8 Noble Auspicious Ones, remember the kindness and deeds of the buddha, practice generosity through mandala offerings and make strong aspirations and dedications for all sentient beings to attain enlightenment.
As Dharma followers, we may sometimes break our vows or commitments (usually called as Samaya) - intentionally / unintentionally - while living our daily mundane lives.
Hence, the practice of Yar Ngo/ Vajrayana is extremely important, as it:
A. Purifies our negative karma and restore the vows /commitments we have broken through confession
B. Accumulate merits through making aspirations and dedications for all beings to attain enlightenment.