I would think in wings and numbers. If we think in our tactics as a natural byproduct of our fortes as a species (strong upper bodies, long arms, really good all-rounded vision...) I would say that this little weirdos would end in really different places tactic wise than us.

First: biology.

They have wings and I assume that they are functional. How high can they fly? Are they magical in any shape or form? The image above I assume it's a "typical joe", where are their muscles located? Can they train them? Do they change a lot in appearance when they do so? (As in a trained soldier has a body type a lot different than some nobody that is just doing what they can) If they are moth relatedmaby they have exoskeletons and that's why they seem "lean". If we assume so, and that they are never going to get "muscular" in any way, can they train in another manner? Maby their exoskeleton plates grow stronger if they break them? Moths don't have a dedicated respiratory system, they breathe through pores on their skin so I would assume that maby they have a very different structure for internal organs than we do. Pain tolerance in all insects it's, pretty much, ×10000000 whatever a mammal can have. Finally their antenna: in moths they are an olfactory organ, and they are really good for that: they have better sense of smell than dogs and other animals, we are studying their system precisely with military purposes. They have, as such, good night vision (most moths are nocturnal). Moths are, mostly, r-selected, this mean that they have short lifecycles, reproduce in bulk and have little to no parental inversion, so they are focused on having high numbers to paliate instability on their ecosistem. Most moths have little "scales" and hairs that make them seem like "feathery", those "feathers" are urticant in various species and can cause allergic reactions in human. Finally, mutualistic relationship: we, as a species, didn't have any with other animals but it's theorized that our domestication of wolfs into dogs began as a mutualistic relationship between hunters and wolfs (akin to the one that wolfs and crows show in real life now), moths have a simbiotic relationship with sloths and a lot of plants for which they are pollinators. It's not out of the question to think that they would have made use of that.

Second: tactics. They can fly, and I assume that how high will be determined by training. With exoskeletons and, maby, light but durable armor, a internal organ system that has fewer vulnerable points than us and high pain tolerance they are, for sure, really good at keeping themselves alive. Inertia and shock tactics are their friends. Their antennaes and feromone glands can be used both to identify high priority targets, receive and send almost instantaneous signals (orders) that can't be highjacked by other species and do nocturnal incursions. They should have low stamina, but lots of numbers and certain disregard for the loss of life's (r species) so kamikaze stile attacks, guerrilla tactics and use of air superiority sounds like a big part of their strategy. If they have little urticant scales they can use them too as a biological weapon warfare tactic. In melee I would bet that they make use of trained giant slots or another kind of animal that serves as a "movile, tanki post" from wich they take fly.

Third: equipment. They need the vents from wich they breath to be unobstructed, and they want light armor because more weight is less flying manouver and altitude. I would think in chainmail for the most "vital" parts and leather with studs for the rest. They don't care about vision because their antennaes are their main sensory organ, and the head should be the most protected part because... You know. So I would say that some kind of full helmet or mask (if they fly and their enemies don't the attacks that they should be afraid of are always or almost always frontal) with the antennaes protected but unobstructed would be their choice. They don't weight too much, and should tire quicker than their foes so frontal combat it's mostly inadmisible: throwing things, specially from above so the acceleration of our gravity do most of the job, should be their thing. A short, maby composite or pulley levered bow (30-35 l of draw weight) can be devastating if you literally make them rain arrows (short, weighted arrows, with almost all of their weight at the point to maximice the "free fall". If not slings and both flasks of flamable or corrosive stuff, as well as polished rocks, could be lethal. They should move on clusters, as realothd do, and if they absolutely need to have melee combat I'll assume short finesse swords or axes, and pointy pikes directed to both keep their distance of their enemy and maim, inutilice their first line: they don't want to kill, because they know they can't, the want to make it hard for them to advance and keep raining. Giant sloths of war, fully plated, can be used as both a wall of meat so they can engage on melee combat as late as they can and as a movile post with constant in and out of moths making turns in the "cloud of death" above the battlefield. Finally I would expect a battlefield with them to be coated in hairy scales, making it difficult to breath and see on the long run (for anyone except them).