You can just have the humans call each other He, She, Person, People.

The other species' then have their own variations of those words. I assume, in your work, that the two species eventually meet up. You can then have the humans do something like the below to teach the reader more about the alien species.

*At dawn we were woken by who we assumed was our guide ... we learned our guide was a 'he' due to the scarcity of his clothing, and though we met others of his species we never saw what could be considered a female ... over the weeks working with our guide we began sharing bits and pieces of our language and culture.*

*I introduced myself as Jack and my partner as Wendy, our guide slapped his chest hard and emitted a sound like "A'chug'nuz", though the 'nuz' sound was beyond the abilities of our body to pronounce. The guide responded to "Achug" and took no offense at our no-doubt butchering of his name. We were overwhelmed with relief that the Achug was intelligent - he immediately grasped that we were interested in his world and readily, even enthusiastically, pointed out things and spat their names out in his brutal language, sometimes giving a brief demonstration of how such things were used.*

... you get the idea. You slowly but surely feed the audience bits and pieces of the other species' way of thinking and their culture and their language. If the language is foreign then you, as the author, decide what the aliens call each other and simplify it for the reader. This, I think,  reduces the likelihood of grotesque infodumps which could be provided to the reader in a more immersive manner.

Edit: short answer: You CAN use he, she, they, people, person in reference to the alien species. Achug is a "He", if their are females they are "She" or "Her", a collective of individuals is a "They" or "Us" or "We". They may call themselves something like "A'Tirkma" which you can simplify to "Aturk" and then call the species "Aturks". "Man" and "Woman" are more human designations so I would recommend finding something else to call your alien species.