In orthodox Tantra, the mantra is inert ( jada ) until activated ( chalita ) by the guru’s shakta (energy transmission) during diksha . Without this, you may chant millions of repetitions and only attract low-level elemental spirits (pretas, bhutas) mimicking the Yakshini. Worse, a mispronounced bija can invite a vetal (vampiric entity).
If you have a guru’s permission to study, consider these sources: yakshini sadhana books
If you wish to study these books, follow this path: In orthodox Tantra, the mantra is inert (