TextEdit: adding a new column

[macstatic]

I expected this to be easy but.... I'm having trouble adding a new column to the beginning (leftmost side) of an existing table in TextEdit (1.9) in OSX 10.9.5 Mavericks.
Whenever I try to add a column (regardless of where I place the cursor) it's added to the rightmost side. What's the solution?

Here's what I do (I've already created and filled in a 24 row, 5 column table):

1) right click anywhere in the table and select "Table" from the pop-up menu
2) where it says "Column", I change this from 5 to 6

 

[ribbo1939]

Here's what I have done and appears to address your problem.
Go to Textedit preferences and change "window size" width from (in my case it was 90) to 100 then open a new doc, go to to the little arrows above the numbered heading and drag each one across the top stopping where you wish. My experiment now shows I have 10 columns

 

[macstatic]

I don't understand. I did what you explained but moving the little arrows around did nothing.
Also, I wanted to add a column to an already existing document with a table in it.

I ended up making the table from scratch again in Pages and I've probably learnt my lesson: don't start anything complicated and time consuming in Textedit. It appears to be pretty limited and not worth the time for anything but very basic text IMHO.