Power Query Mapping Table question

[iosiflupis]

I have three different power queries that I would like to merge. They share column names but there are some column names that are only used in one table and not the others. I am working on a mapping table in excel. I was going to use the table with the most column names and pull the other two into that table. How do I set up the query so that the tables without the fill to the main table, and how do I pull in the column names that are not in the main column?
Here is a portion of the table that I will be working with:

 

[GraH]

If you want to combine the queries (I understand append, while you say merge) simply do the append. All columns, regardless from which table they originate, will appear in your result.
From the screenshot, you do not seem to rename stuff, so there is no need to make it this difficult.

 

[iosiflupis]

After looking at the three files, I noticed that there was no way to join the tables in any way. There was no one specific piece of information that was unique to each record in each file. So, I am looking at different data that will give me the same answers. Thank you for your assistance.