Blocks can be mined with Pickaxes and placed in the world. Some blocks are also used in crafting, for example Ice or Crimson Cobblestone . Blocks will be auto collected in close proximity to them. A block exclusive inventory exists along side the players character inventory. The block inventory will store all the blocks and provide access the blocks at any time. There are two pages to the block inventory.
To withdraw blocks from the inventory just click and drag to the action bar or click the arrows on either side of the inventory to drop into the character inventory.