If you've dealt with Joomla articles before, it's only natural that you'll expect K2 to be as difficult as Joomla's content. But it's not. It's actually a lot simpler and saner to use.

You define some global layout settings in the K2 component parameters (menu "Options" in the K2 backend). These affect for example how user pages are rendered. Explore the settings to understand more.

Then you have your K2 categories. In there, you can define precisely how items are displayed in listings and individually. For example (as you mentioned), you can show the image and introtext (=teaser text) in listings (itemlist view) and expand to more elements in the item view. If you are new to Joomla overall, make sure you "split" your content in the WYSIWYG editor to get introtext & fulltext. Alternatively, in the K2 Options (Advanced tab), enable the option to use 2 editors instead of 1.

After K2 settings and category settings are applied to the output of K2 content, you can override some of the display settings when you create a menu item to multiple categories. This allows to normalize some common category display settings like the grid in which items appear (one category may have a 4x4 grid, another a 1x8 - this way you can enforce a new grid).

This is the order of how you control content display settings in K2. You can always of course download the K2 demo site (www.joomlaworks.net/joomla-templates/free-templates/takai?ref=k2demo) and experiment with a site that's ready-made.

If you like video tutorials, check this out: getk2.org/documentation/k2class2012

Welcome to K2 :)

Great!