I've imported a mesh and an armature and parented them. There are two little green men in the outliner and one is the Pose I have worked hours on. What is the other one, where the little man is holding a square. Is this reset pose? When i click it, i loose all my work.
The green man icon with the square indicates (and when clicked accesses editing of) the skeleton, rig, or Armature. It is about the number of Bones in the Armature, their relationship to each other, and their base position and rotation. (So even though it is the armature icon, an armature has a base pose, because it cannot not have one.)
The green man icon that kinda looks like its running indicates (and when clicked accesses editing of) the Pose, or poses (That means poses that are different from the base pose of the Armature).
When you click on the pose icon, edit a pose (for instance move an arm up), and then click the armature icon, you should see (and be able to edit) the armature (in its base pose, with the example arm back in its base position, like it hasn't been moved).
But if you then click on the pose icon again, you should see the edited pose (with the arm moved up) again.
I have come across situations though, where editing the Armature resulted in loss of the pose (at the current frame). But you can save your pose by either adding a keyframe for the bones in the Armature, or save the bone position and rotation in the Pose Library.
I advice the latter; then you can always keyframe them later if needed.
Select your armature, go to Pose Mode. Then Properties > Object Data Properties > Pose Library > New. Then select the Bones for which you want the position an rotation saved (or simply select all of them) and click Add Pose (the little Plus icon). Now you can reload the pose by clicking Apply Pose (the little magnifying glass icon).