Basic gossip menu

local function Hello(unit, event, player)
    unit:GossipCreateMenu(100, player, 0)
    unit:GossipMenuAddItem(0, "Do stuff", 1, 0, "Are you sure?", 100)
    unit:GossipMenuAddItem(0, "Close", 0, 0)
    unit:GossipSendMenu(player)
end

local function Select(unit, event, player, id, intid, code)
    if(intid == 1) then
        -- do stuff
    end
    player:GossipComplete()
end

RegisterUnitGossipEvent(ENTRY, 1, Hello)
RegisterUnitGossipEvent(ENTRY, 2, Select)