Could anyone please explain in-depth, because I'm having trouble understanding it.
"A data store is essentially a long list. Each entry in this list has two parts, a key and a value. The key is the name used to find an entry in the data store. Keys must be strings. The value is the information you want to store or access. Values can be numbers, booleans, strings, or Lua tables. However, values cannot be ROBLOX types like Vector3, Instance, or Part."
~ROBLOX Wiki
Think of it like this, there's a key, you can create a key, and store data inside that key.