I think that in the suttas the path to higher realms is described as "bright kamma". There are four types of kamma:
- Mixture of bright and dark
- Kamma which leads to the ending of kamma
It's the latter which leads to nibbana.
I don't know a good summary.
You could search Access to Insight for text containing "bright kamma" -- https://accesstoinsight.org/search_results.html?q=kamma+bright -- because that text is likely to include descriptions of the fourth type too.
The most relevant paragraphs from Kamma & the Ending of Kamma might be these:
Most descriptions of the Buddha's teachings on kamma tend to stop here, but there are many passages on kamma in the Canon — and included in this section — that do not fit into the neat picture based merely the first two insights on the night of the Awakening. The only way to account for these passages is to note the simple fact that Buddha's teachings on kamma were shaped not only by these two insights, but also by the third insight and the resulting knowledge of Unbinding. The third insight explored the possibility of a fourth kind of kamma — in addition to good, bad, and a mixture of the two — that was skillful enough to bring about the ending of kamma [§§16-17]. At the same time, in the course of developing the level of skillfulness needed to bring kamma to an end, the Buddha learned a great deal about the nature of action that forced him to recast his understanding of kamma in much more subtle terms. The knowledge of Unbinding — which followed on the full development of this fourth type of kamma and the realizations that accompanied it — acted as proof that the understandings comprising the three insights were true. To explore these points will not only help give us a more complete understanding of the Buddha's teachings on kamma, but will also show why conviction in the principle of skillful kamma is essential to Buddhist practice.
In his effort to master kamma in such a way as to bring kamma to an end, the Buddha discovered that he had to abandon the contexts of personal narrative and cosmology in which the issue of kamma first presented itself. Both these forms of understanding deal in categories of being and non-being, self and others, but the Buddha found that it was impossible to bring kamma to an end if one thought in such terms. For example, narrative and cosmological modes of thinking would lead one to ask whether the agent who performed an act of kamma was the same as the person experiencing the result, someone else, both, or neither. If one answered that it was the same person, then the person experiencing the result would have to identify not only with the actor, but also with the mode of action, and thus would not be able to gain release from it. If one answered that it was another person, both oneself and another, or neither, then the person experiencing the result would see no need to heighten the skill or understanding of his/her own kamma in the present, for the experience of pleasure and pain was not his or her own full responsibility. In either case, the development of the fourth type of kamma would be aborted [§§228-229].
To avoid the drawbacks of the narrative and cosmological mind-sets, the Buddha pursued an entirely different tack — what he called "entry into emptiness," and what modern philosophy calls radical phenomenology: a focus on the events of present consciousness, in and of themselves, without reference to questions of whether there are any entities underlying those events. In the Buddha's case, he focused simply on the process of kammic cause and result as it played itself out in the immediate present, in the process of developing the skillfulness of the mind, without reference to who or what lay behind those processes. On the most basic level of this mode of awareness, there was no sense even of "existence" or "non-existence" [§186], but simply the events of stress, its origination, its cessation, and the path to its cessation, arising and passing away. Through this mode he was able to pursue the fourth type of kamma to its end, at the same time gaining heightened insight into the nature of action itself and its many implications, including questions of rebirth, the relationship of mental to physical events, and the way kamma constructs all experience of the cosmos.
I'm not sure whether you can follow (make sense of) that description to its end.
I like the Vajira sutta -- it matches the last paragraph quoted above, and is an observation of the tilakkhana.
Also there's a description of how to eat mindfully, which appears in several suttas and might help to illustrate:
And how does a monk know moderation in eating? There is the case where a monk, considering it appropriately, takes his food not playfully, nor for intoxication, nor for putting on bulk, nor for beautification, but simply for the survival & continuance of this body, for ending its afflictions, for the support of the holy life, thinking, 'I will destroy old feelings [of hunger] & not create new feelings [from overeating]. Thus I will maintain myself, be blameless, & live in comfort.' This is how a monk knows moderation in eating.