Go to your character page(where all the stats are) and scroll down to the bottom, you'll probly see 2 options, skip the fun and an option to make the character your main.... type in your password into the box then click on the button and it will make that character your main account. Then go to the Equipment page and there will be a new chest icon next the the bolts icon called "Marketplace", thats it.
P.S. You cant use the marketplace if you havnt made the character your main OR if you've used the "Skip the Fun" option.
