Sending message to get variables

I am interested in making a program that when u send message over rednet to computer2. Computer2 sends back variables that are listed in computer2. Also way to send variables back to computer2 and list them with id in computer2. New update overwrites old.

I dont know where do i start making it, thats why im asking for help how should it go.

This wiki page should get you quite far on getting started:

http://computercraft.info/wiki/Rednet_Tutorial

Using tables could work, try this?

-- Table with the variables it must send back if it has the correct received one
t_table = {
    ["Var 1"] = "You sent me var 1!",
    ["Var 2"] = "You sent me var 2!",
    ["Var 3"] = "You sent me var 3!",
}

while true do
    senderID, msg = rednet.receive()
    if t_table[msg] then
        rednet.send(senderID, t_table[msg])
    else
        rednet.send(senderID, "That variable is not saved in my computer.")
    end
end