Need help with a few things please

Greetings, So im a newbie to Wordpress and im getting so frustrated with a couple things for now. One is how can I remove the author name on each post? It says posted by admin but I want to remove it completely. I've tried 2 plugins and they didnt work, also 2 different CSS code and they didnt work either. What am I doing wrong? Second is, on the first page I want the "Hem" content be together with the "Nyheter" content but I want it all to be on the "Hem" button which is the startpage. URL is http://brfdomnarvet10.se/ Help!