My Booth
You can list items that you want to sell in Trade House via Trade House - [My Booth].
Booth Types
There are two types of booths: [Normal Booth Tabs] and [Premium Booth Tabs]. The only difference between them is the number of items allowed to be listed.
Premium Booth Tabs are available for purchase in [Shop] - [Account], and there's a cap on how many of them you can buy each season.
Normal Booth Tabs are free, but the number of slots you get to unlock depends on your level, You start off with 3 slot(s). As you reach Lv. 70, you unlock 6 slots, and by Lv. 90, you'll have 9 slots at your disposal.