How do I edit the code of a WordPress site?

The easiest way is indeed to have an FTP access and edit the blog's theme directly (in /wp-content/themes/nameofyourtheme. Otherwise, you can also do it from the Admin panel. Go to Appearance, then click on "Editor". You'll then be able to edit all the theme's files.

Edit:

If you want to change the layout of the posts, the file you'll want to edit is single.php.

You can edit the site through the dashboard. When you are making a post you can change it to html and create your own things.

Unless there is a plugin for this. Which there might even be. But, since i have no idea and fast googling said nothing.

You will have to edit the theme files /wp-content/themes/Your-Theme/

You will have to take something like <?php comments_template(); ?> from single.php file and move it to index.php file somewhere after where you should find something like this <?php the_content(''); ?>

• single.php Holds the article page.
• index.php Holds the "home" page.

Is this hosted in wordpress.com?

In the control panel you can find Appearance > editor in there you can edit the files. Thought i think that it is very likely that you wont be able to save your edits due to file permissions.

Also if its a paid hosting they quite often send you these details on email.. I mean Ftp acc and pass.