Yeah, we should butcher the Gazelles, as we are the one with a good knife and some butchering experince. Have the rest of the tribe gather sharp rocks and pieces of wood for handles, so we can teach them how to make their own knifes, so they can help us butcher kills latter on. With the meat we should do as Dragor23 suggested, dry it and save it for latter. If we don't have drying tech just take it back to the cave. With the skin we should make cloths out of it, once all the flesh is removed. We have a cave already so I see no need for tent in the near future. I don't think we would need backpacks either as we have few things to carry as of now, and we can make back sashes out of plant fibers that could increase our carrying capacity to hold more things. Oh and make sure to cut off the antlers of the Gazelle, as those can be made into tools. If we don't have the knowledge to make tools out of antler for now in the mean time we can display them above the cave to show off. Once we finish all this have a party, and make sure to initiate child production, our tribe needs some more people.
I agree that in the future we will find ourselves in need of backpacks and tents, likely the latter before the former, but we need some proper cloths first to protect us in the winter and once we kill more things we can begin making tents. Backpacks will only become necessesry when we have a large number of possesions and we need to move around a lot. Totally agree with the boon tools, as bon is easier to shape than rock it can be made into a much more precise tool.
On second thought though the plan articulated in the first paragegraph should be carried out like so: 6 people go back to the cave, including you in the 6, carrying the the Gazelle corpeses. 5 go collect sharp stones and pieces of wood to make knives for the rest of the tribe. When 6 people arrive at the cave everyone but you leaves to go and collect more sharp stones and pieces of wood. You begin to butcher the Gazelle, putting the meat on the cleanest part of the cave you can find, puting the bones in a pile, and stacking the hides. When everyone is back they (and you if you are finished) begin cooking the meat. We then have a party and begin the process of making children.
We will save the other materials for the uses articuled in the first paragraph, which should be completed later.