Rasarnavasudhakara 3.34

Now, the five stages of action (avasthā):
The stages of action are fivefold, determined by the actions of the hero and others: / beginning (ārambha), effort (yatna), hope of attainment (prāptyāśā), certainty of attainment (niyatāpti), and arrival of the fruit (phalāgama). / Among these, mere exertion toward the primary fruit is held to be the beginning. // 23

As in the opening juncture (mukhasandhi) of the Bālarāmāyaṇa, the mere determination of Rāma to attain extraordinary excellence is the beginning.