One and two are very easy.
You insert a value to the database using .insert() and in the .then() part you .refresh() the dataset.
Number 3 is a little bit more difficult and depends on how many users you have.
If you don’t have a too many users, you can query the database every second or two and if the collection has been changed, refresh the dataset.
If you have a lot of users and you’re afraid that it’ll be too many queries per second, you can install one of the web socket NPMs and use them to update the users in real time.