category search to view as the archives page

hi, i hope someone can give me a hand with this.

i whant that (with my selecta theme) when you click on any tag link or category link you can see the listing just as it apears in the “archives” page of the theme (or like in the OCMX thumbnail widget ). y mean, y whant the tumbnails of each post, intead of the post with the image, ecperv,etc,etc.

y made some tryals with the “arcvhive.php” file, but i cant get it rigth……………..any clues?

(i would leave you a link to my blog, but i have it in localhost)