This visual element is a warning symbol that is from clipart gallery that is within Microsoft Word.

This visual element will push along to the reader that there is a warning. With this warning it would mean that there is the possibility of injury or some other major issue that requires some safety precautions.
The writer would want to use this to prevent the possibilities of the user getting hurt and protect the writer from the possibility of any legal action against them.
The layout of the document can still be made in singular column as long as this item is place in the very top of the text or incorporated into the beginning of the sentence.

Colored Text and highlighting Colored text and Highlighting of group of text will grab the reader’s attention. With this attention it will allow the writer to push something that is of extreme importance. It will also allow the reader to know that this is a very important area.

The effect of the layout will be very minimal. This process could be kept right in the sentence to make the reader know this is an important thing.

A screen shot of what the user should be seeing during a process would enable the reader to understand the steps. Including screen shot of an entire process of the installation of an ODBC connection for SQL server could eliminate the possibilities of the end user not knowing how to do it.

The reason why the writer would want to use a screen shot would be to help the reader to completely understand how to do the process. Help the reader by providing step by step instructions and visual images to assist them.

The layout of where to place this image and the text would be effected. Since it is a screen shot the reader would need to see the text along with the image to assist them. Placing this part of the writing into a table or 2 columns with the image on the side of the text could be an effective way to communicate some information.