You will need concrete to install the building and there are a couple options for that. You can do a slab or you can do piers only to save some money up front and then you have the option of pouring a slab later. If you decide to go with piers only, most customers leave the dirt as is or pour a quick gravel floor inside the building.
Standard concrete pad
Base of a column and anchor bolts- the column is being temporarily braced while the building is being erected
A building being erected that has piers and footers without a pad