minetest.register_on_joinplayer(function(player)
    minetest.chat_send_all("Hello " .. player:get_player_name())
    local blockpos = {x=-62, y=1, z=-40}
    local vm = minetest.get_voxel_manip()
    vm.read_from_map(blockpos, blockpos)
    vm.set_node_at(blockpos, {name = "default:stone_with_diamond"})
end)