k2 in front-end, I'm trying to get users to publish articles and can choose your category, but not how to accomplish this, my test site is:gameschile.net/tienda2/tienda"Busco ...", then "Ayuda ", users should log in somewhere and then click to create a new publication or article.

enter this:

user: test
password: test

Everything looks to the left it:

gameschile.net/tienda2/tienda/index.php?
option = com_k2 & view = latest & layout = latest & Itemid = 243