You can view general WordPress help on webmaster website at these links:
Additional instructions specific to your website follow:
MEDIA – HEADERS
Go to Media to upload (Add New). Select image, upload. Select image again, click Edit Image below. Scale to 2000 wide (delete width, insert 2000), Scale, close. Select image again, Edit Image, place cursor in photo to drag a box, under Image Crop edit Selection to 2000 and 1200, then drag box up or down as desired for slice (with the most interesting part centered), then click the Crop symbol upper left, click Save under image, then Update or Save or Publish if necessary.
Your site is currently set up to allow new accounts. Most of them are spam.
All of the below was on a sample page showing a few styling methods.
This is an example page. It’s different from a blog post because it will stay in one place and will show up in your site navigation (in most themes). Most people start with an About page that introduces them to potential site visitors. It might say something like this:
Hi there! I’m a bike messenger by day, aspiring actor by night, and this is my website. I live in Los Angeles, have a great dog named Jack, and I like piña coladas. (And gettin’ caught in the rain.)
…or something like this:
The XYZ Doohickey Company was founded in 1971, and has been providing quality doohickeys to the public ever since. Located in Gotham City, XYZ employs over 2,000 people and does all kinds of awesome things for the Gotham community.