Black Lion Trading Company

Hi there.As a relatively new player please could you help me understand something. Why do you have to run around looking for a Black Lion Trader when you sell items - shouldn't the money appear directly into your coffers, also the same with buying items - if for example, I need an item of weaponry in a hurry, why can't it appear in my leather bag straight away. Am I missing a trick here or is this how its usually done?

Thanks,Gavin.

That's how it is done.
https://wiki.guildwars2.com/wiki/Trading_Post#Pick_up

Since one can not pick and choose what to pick up from the Trading Post, it's best to only pick up when one is prepared (inventory-wise) to do so.

You're not missing anything - if you want to collect gold or items from the TP you need to find a Trading Post NPC to collect them from. They should be easy to find however - every city has at least 1 Trading Post 'office' with 3 NPCs, usually near the bank and always marked on the map. They're sometimes found in other locations too, and again will be marked on the map so you can find them easily without having to run around looking for them.

I'm not sure why it's done this way, but it's been like that since GW2 was released.