Hi all im a fairly new user and i have looked around in the market place quite a bit and found quite a few things id like to get

my problem starts that they all say DM me and i assume from what i have seen and reading rules (direct msg)
but i just cant figure out how to DM anyone i try adding them to contacts but they dont show up when i go to chat

can someone give me a quick run down on how i can contact ppl dm or other way cuz im really not getting it, is there an account limitation im not seeing?