This is useful if you are working on an analysis and have a table that you can save as a csv file and want to include in the paper. You can edit the table, by clicking on the table and setting the first row to be the header, and make other adjustments. Note that as you upload the CSV file, Authorea inserts a data icon next to the table. If you want to change the header, etc, you need to edit the CSV file and do it that way. Remember that on the Authorea webpage itself, you can only insert the caption and Authorea controls the Table number and layout. However, when you export your document to other formats, you will see that Authorea will correctly align the Table number and the table caption. You should always add a caption to your table.
The other option is to use a Markdown table. In order to use a markdown table, you specify a table like as follows in a Markdown block: