You may be thinking, "I'm not a brick layer, not a doctor,". Good. A doctor gives medical treatment. You probably shouldn't be doing that. This article is about keeping someone alive till a doctor can treat them.
First chance you get, take a real First Aid course. This web page covers only some bare essentials.
First aid is TEMPORARY. It is a 'quick fix'. Your concerns are
1) keeping a victim alive
2) keeping them from getting worse than they already are, and
3) Keeping them comfortable.
The most common situations in the wilderness or other 'primative' living conditions that will quickly threaten a victim's life are
1) Lack of heartbeat
2) Lack of breathing
3) Loss of blood
4) Loss of body heat, and
As a warrior, you really should learn CPR. It can restore both heartbeat and breathing. This is something you aren't going to learn reading a web page. Take a class. You may well save the life of someone in your clan. Check with your local Red Cross. Many schools, Scout Troops, etc. offer CPR classes as well, often for free.
The most effective way to stop bleeding is with pressure. Apply pressure directly to the wound, or if that's not practical, apply pressure to the nearest artery between the wound and the victim's heart.
You should certainly try to keep a wound clean, but remember that a doctor can always treat for infection unless the victim has bled to death while you are looking for clean bandages or rags!
Hypothermia is possible anytime a person is in shock, overly tired or hungry, and the air temperature is below 80 degrees. Hypothermia is when the body is unable to produce heat fast enough to keep the core temperature above 95 degrees or so.
Wind and water make hypothermia more likely. Water conducts heat away from the body. When the wind helps evaporate water off the body, further cooling is produced.
A person suffering hypothermia may not feel cold themselves, but they will feel cold to you. They will usually be very tired, and will be mentally slow, often acting or sounding drunk. They will frequently be uncooperative, wanting only to rest or even sleep, which can actually be fatal if allowed
First Aid for hypothermia is straightforward. Get the victim warm. Get them in a blanket or sleeping bag. If their clothes are wet, strip them off first. They might be embarrassed (or you might), but body shame isn't worth dying for.
The quickest way to raise their core temperature is with a hot drink or soup. Use your head and your resources. If the sun is bright and warm, lay them in the sun. If you can build a fire quickly, do that. You might have to get inside the blanket or sleeping bag yourself to warm them with your body heat. (Better to be able to share crude jokes about the experience later, than to attend their funeral knowing you might have kept them alive.)
Once the victim is fully warmed up, give them something to eat and let them rest.
Poisoning in the wilderness is usually from eating or drinking the wrong thing or being snakebit, scorpion stung, etc. Generally, for internal poisoning, give LOTS of water or milk. (Vomitting may cause further damage, depending on the poison - if you don't know, make them drink.)
For external poisoning, keep the affected body part lower than the rest of the body, keep the person inactive to slow the spread of poison. Most first aid courses do NOT recommend tourniquets any more, nor do they recommend cutting open the bite to suck out the poison.
In any case of poisoning, get the victim to medical care as soon as possible.