The idea is that meaning does not necessarily have to be empirically discovered in the external world in order to function psychologically. Historically, most people did not discover meaning individually; it was embedded into religious or philosophical systems that explained why life mattered. For example, religions assign meaning through divine purpose, cosmic order, or moral duty. Even secular philosophies can do something similar.
What I am referring to is deliberately adopting or constructing such a framework so that your existence fits into a larger explanatory structure. Be it religious metaphysics (i.e., existence serves a divine purpose, even if that purpose is not immediately visible), or philosophical metaphysics (i.e., certain interpretations of existentialism where meaning is created through will or personal values, though this could arguably be seen as self-contradictory), or cosmic or deterministic views (i.e., seeing yourself as part of a broader unfolding process of the universe, where individual existence is simply one component of a larger system).
The main point is that meaning is not necessarily something that must be “found” in the external world. It can be logically justified through a framework that gives existence an interpretable role. There is also a question of what meaning even is, and what exactly qualifies as a proper meaning in life? In a sense, you could justify meaning if you could prove normative realism, which is not a major leap since normativity is strongly tied to meaning (I suppose it can also be found through some sort of aristotelian teleology and pursuit of eudaimonia).
