How trade works?

[Tracekun]

Sorry to bother you, but can someone tell me where I can find a guide to trading?
Searching the forum, I found a guide with theese abbreviations used in chat:
 

Spoiler

"Wts" ~ Want to sell, most basic term used, indicating a player wants to sell said object.

"Wtb" ~ Want to buy, another basic term, indicating a player wants to buy said object.

"Offer" ~ Offer, usually means that a person hasn't got a price for said object, but is looking for offers.

"Pm" ~ Private message, the seller or buyer wants you to send them a message about said object.

"B.O" ~ Best Offer, meaning that the best offer another player has offered on said item is [the amount indicated]

"Lfm" ~ Looking for more, The seller will usually indicate the best offer, but use this after.

"C.O" ~ Current offer, pretty much the same as B.O.

"Insta" ~ Instant price, meaning that the seller or buyer will buy it instantly for set price.

"Wtt" ~ Want to trade, Indicating that a player doesn't want to sell for a Pokedollars, but an item/pokemon instead.

 

But how does the trading work?
when someone answers to my announce via pm, how can be done the exchange itself?
 

Edited 26 minutes ago by Tracekun