Stabilizer map on transitive G-set defines a morphism with G acting on subgroups by conjugation

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This is part of a homework problem for a graduate course on abstract algebra.

Given a transitive G-set $X$, show that the map that assigns to $x \in X$ its stabilizer defines a morphism of G-sets with G acting on its set of subgroups by conjugation.

I'm very much confused by this.

So we have a transitive G-set $X$, which means (among other things) every orbit is equal to all of $X$ (alternatively, it has only one orbit).

We also have a map $f: X \rightarrow S$ given by the rule $f(x) = stab_G(x)$, where $S$ is the set of subgroups of $G$.

A morphism of G-sets would be a map $h: G_1 \rightarrow G_2$ such that $gh(x) = h(gx)$ for all $g \in G$.

But part of the specification of this morphism is that G is taken to act on its subgroups by conjugation.

I'm completely confused by this. I don't see how to use our function on a fixed G-set to get a function between arbitrary G-sets (or if this is even what's expected), I don't see how the action of the G-set (by conjugation over subgroups) falls into place, and I'm a bit confused by the change in the action from when we specify our $X$ (by specifying that it's a G-set, we must already have an action) to the new action by conjugation.

I also realize that this would be more appropriate of a question for my prof/TA/classmates. I was planning to ask on Monday but forgot about the statutory holiday (it's due Tuesday morning). I'm not seeking a solution, just help in understanding the question.