Some of the more complex content types require a bit work to create, but there are many types that are very simple to make.
Install the H5P plugin
In the dashboard of the blog you would like to create content, visit the Plugins section and activate the plugin.
This will add an H5P section to the sidebar of the Dashboard and H5P Content to the +New menu in the admin toolbar.
Creating Content
When you want to create a new piece of content you either choose Add New from the sub-menu of the H5P section of the Dashboard:
Or Choose H5P Content from the + New menu in the admin Toolbar:
This will take you to the Add New H5P section of the dashboard.
This section lists all the different types of H5P content you can create. The First time use create a particular type of content you need to Get that content type. This adds the necessary code of that type.
You can click on the name of a content type to find out more details, visit a demo and then Install that type.
After Installing the Plugin you can Use it to create content of that type. Each content type has different features. Here is an example of the steps needed to create an image with multiple hotspots: Multiple Hotspot Creation.
There are a lot more detailed tutorials for adding different content types on the Tutorials for authors page on the H5P site.