How locators are used?

Dear Experts,

We are going to use the locators for some of the Items in the Inventory. So please suggest me while doing the setups of Inventory Organization which level will be used :

Select a locator control option:
None: Inventory transactions within this organization do not require locator
information.
Prespecified only: Inventory transactions within this organization require a valid,
predefined locator for each item.
Dynamic entry allowed: Inventory transactions within this organization require a
locator for each item. You can choose a valid, predefined locator, or define a locator
dynamically at the time of transaction.
Determined at subinventory level: Inventory transactions use locator control