When working on a construction site, you are likely going to have to offload supplies from lorries and tractors. This is not going to ve the same simple process as if you were in a warehouse. You do not have a flat indoor surface to help you. So, how can you complete this task safely?
Ideally, you want to use any heavy lifting equipment that is available to you. This can include chain hoists, lifting slings, and forklifts. These pieces of equipment will help you to be able to offload the supplies safely onto your construction site.
Even before work beings, you should think of ways to make this a safer process. Why not mimic an area like a warehouse for where the supplies can go. Take an area of the land and have it flattened to create an area that is safer for offloading and storing these supplies.