The two column text block component is found on Landing Page Content Types.
When published, a two column text block component looks like this:
You can make as many two column text blocks as you like on a page. Below is what two separate two column text blocks could look like:
When you are creating a landing page and want to add in two column text block, you do so in the page content part of the Landing content type by clicking on the arrow next to add child page tiles and the other page content types appear. You can then select add two column text block from the drop down menu. See below what it looks like:
Once you select Add two column text block, you then get the following input screen:
You will notice that the section titles are not mandatory and can either be used or partly used. As the examples above show of how these two column text blocks look, the first two column text block used both section titles, but the second two column text block only used the left hand one as both text blocks obviously related to the same heading. This allows for a variety of use with these. The text block areas themselves allow for adding simple text, text that is linked, or adding in images. Again the samples above show how these have been used.
Once you have completed this section that is all you do as there is no individual 'Save' button for a component. Components are saved when you save the page.