Can I see a simple mod example for placing a block? Somehow this:
function on_mods_loaded()
  minetest.debug("Hello, world!");
  minetest.debug("Registering Janet…");
  minetest.register_node(":frog:janet", {
    description = "Janet Block",
    tiles = {
      "janet.png",
      "janet.png",
      "janet.png",
      "janet.png",
      "janet.png",
      "janet.png",
    },
    groups = {crumbly = 1}
  });
  minetest.debug("On player connect, create and send the first player to Janet…");
end

minetest.register_on_mods_loaded(on_mods_loaded);

function on_newplayer(player)
  minetest.debug("Player connected. Setting down Janet…");
  minetest.emerge_area(vector.new(0, 0, 0), vector.new(0, 0, 0), minetest.place_node(vector.new(0, 0, 0), {name="frog:janet"}));
  minetest.debug("Sending to Janet…");
  player:set_pos(vector.new(0, 101, 0));
end

minetest.register_on_newplayer(on_newplayer);

is not getting the job done.