The wounds need to be covered with possibly a sterile textile. Sterile bandages are basic ingredients of every first aid kits. The injured limb or body part needs to be immobilized in the position we found it by using any available implements. Be creative: immobilization can be done using a ski pole, a piece of wood or any other stiff objects.
A closed fracture may be suspected if you see the following signs: pain, swelling, redness. Moving the affected limb is either very painful or limited, and in some cases, the patient is unable to move the limb at all. In case of a more severe fracture, deformity may be apparent even by looking at the limb. Call the ambulance, don’t leave the patient alone before they get there, and don’t move the injured limb!
We mustn’t forget during first aid at the site of the accident that beside the suspected bone fracture, the patient may have other injuries too. Try to notice these injuries and address them at your best level.