The words "here" and "there" can be modified by other prepositions: "under here", "over there", "out there", "in here" and so on. These combinations operate as a unit.
When "out here" is used by a speaker usually refers to something close to the speaker, but external or remote to some other location being considered, like the location of the person being spoken to, or some context being previously discussed".
If someone is inside a building, you can use "come out here" to ask that person to emerge. The "here" refers to where the speaker is, and that is "out" relative to the person being spoken to.
"Your shoes are out here" is the simple "out here", like in "come out here". Your shoes are here where I am, and relative to you, that is outside.
Someone narrating a story from the field might use a sentence like "out here in the wilderness, you must be self-reliant." Here, the speaker is communicating that he or she is in some location that is remote to some imagined point of departure to which either the speaker, or the people being addressed, have a relationship. This is important because the difference between that reference point and the "here" place is being stressed. A sentence like "it's cold out here" implies a contrast: "It's cold out here, compared to the understood reference place I have in mind".
The other locations like "up here" can be understood similarly. If you venture out to the roof of a high rise building you might say, "What a great view you can enjoy up here", which is a little bit different from just saying, "What a great view you can enjoy here". It also subtly implies that there is a lower place that the speaker has in mind, which in specifically does not have a great view compared to "up here".
In summary, "here" is a specific place, close to the speaker, and if another word is added like "up" or "out", then it brings in a second location. That location might be used to create a comparison or contrast, or simply to relate to another person's location.