How to view posts the same way they are in the preview?

Dear friends,

I have chosen Trident Lite to create my website, but my posts do not appear on the main page as they do in the preview, or else, with a larger picture for the most recent post, two smaller ones at the right and other posts below. Mine only appear as if they were the posts below. Sorry if this questions is very obvious, but I am getting started to the WordpPress world. If anyone can help me fix this, I will be really grateful.

Best regards,

Gustavo