If you're in hospital, then call for help.
If you see someone fall over, don't be in a rush to get them up. Keep an eye out for dangers & tripping hazards as you approach the person & check that they're responsive & breathing - if they are, carefully put them in the recovery position & keep their airway clear. If they're not breathing call 000 and begin CPR immediately or follow their instructions.
If the person is responsive, try & ask them what happened but don't stress them if they're confused. Check for injuries and apply pressure to any bleeding if you can. If you know (or think) that they've fallen from a significant height & may have suffered neck or spinal injury, don't move them. Keep them calm and stay with them until a paramedic arrives. Not all injuries will be obvious & the person may not feel where they are hurt - this is particularly important with diabetics so be especially careful when helping them.
In an emergency, always call 000.