Omeka, unlike other platforms, does require some ability with HTML and CSS. The good news is, the better you are at markup, the more you can customize your site! I only had a bit of experience through a class I had taken last fall, so I kept to the basics, but do try playing around. In case you don't have much experience with HTML or CSS, the links on this page should help you enough to get your site going.
This is a rather lengthy, but informative, Lynda tutorial. You'll have to authenticate in to watch it
To link items to text, as I did in my exhibit, you will need to use Span tags. All of this markup will happen within the Source section of the WYSIWYG editor. An important thing to remember about span tags is that you need to close them! There's no error if you forget, the link just won't work and then you need to look over your work to see where you went wrong.
Short video on span tags: https://youtu.be/UuwiVehV27w
Please be sure to keep users with accessibility issues, such as cognitive and visual impairment, in mind when designing your site. The guidelines established in the WCAG 2.0 give ways to make your Omeka site accessible to such users.