How does Datastore and tables work exactly?

Firstly, you need to think of a table like a list, with the "index" and the "value". The index is the position in the table, so if you picture it like the following:

local NameOfTable = {
1 = Value1,
2 = Value2,
3 = Value4,
4 = Value5
}

The index, starting with 1 onwards, shows the position, and the Value is what you put in the table.

The values can be anything: numbers, strings, vector3s (etc.) and even other tables!

Now, onto indexing...

Lets use the following table as an example:

local Table1 = {
"lol",
"this",
"is",
"really",
"fun"
}

At the moment, I only have strings in my table (to hopefully make it easier to understand).

To grab something out of the table, I can use the index:

print(Table1[2]) --This will print the second value in the table (i.e. "this")

I can also change values using the index:

Table1[1] = "I know"

This will change the first value (i.e. "lol") to "I know"

Another way to get the index (if you don't know) is to use a loop:

for index,Value in pairs(Table1) do
print(index, "=", Value)
end

This will print the following into the output:

1 = I know 2 = this 3 = is 4 = really 5 = fun

To insert a value into the table at the end, you can use:

table.insert(Table1, "lol") --This will add a new value at the end of Table1

OR

Table1[#Table1+1] = "lol" --Essentially by using an index at the end of the table

To remove the value:

table.remove(Table1, 6) --6 being the index of what you want removed

OR

Table1[6] = nil --nil being the default for an empty value

String indexes:

Table1["Hi"] = "Troll"

print(Table1["Hi"]) --Prints "Troll"

"How do datastores work with tables?"

I think I know what you mean by this, so the first thing you need to know is the datastore functions.

You will need to grab your datastore first by using the GetDataStore method on the DataStoreService:

local Datastore = game:GetService("DataStoreService"):GetDataStore("SomeRandomName")

"SomeRandomName" is the name of the datastore which you want to put your data into.

Next, the actual get/set/update methods:

SetAsync - The method of "saving" data to the store

local Value = 20 --What I want to save to my datastore
local Key = "SomeOtherRandomThing" --Up to 50 characters

Datastore:SetAsync(Key, Value) --This will save the value into the datastore under the name of "SomeOtherRandomThing"

GetAsync - The method of "loading" data from the store

local Key = "SomeOtherRandomThing" --Same as previous

local Value = Datastore:GetAsync(Key) 

print(Value) --prints 20

UpdateAsync - The method of getting the current data and replacing it

local Key = "SomeOtherRandomThing" --Same as previous... again

Datastore:UpdateAsync(Key, function(OldValue)
print(OldValue) --prints 20
return OldValue +20
end)

...And if I was to use GetAsync again and print the value, it would print 40.

Now to answer your question

You wanted to manage tables in your datastore? Well, that's not much different:

I'd firstly recommend you use UpdateAsync if you are simply adding/removing entries.

local Datastore = game:GetService("DataStoreService"):GetDataStore("SomeRandomName")

local Key = "ExampleKey"

Datastore:SetAsync(Key, {"Hi", "lol"})

wait(5)

local NewEntry = "Hi there"

Datastore:UpdateAsync(Key, function(CurrentTable)

table.insert(CurrentTable, NewEntry) --Adds a new value to the table

return CurrentTable --Updates it

end)

And you can use a similar code to remove the values from the table (using table.remove)

To completely clear the table, just do:

Datastore:SetAsync(Key, nil) --To make it empty

OR

Datastore:SetAsync(Key, {}) --To make it an empty table

I hope this answered your question, and as I've said before, PM me if you have any questions...