Just to recap, you are restricted by the width of your body text area to the number of columns you can have, but there is no restriction on the number of rows you can have. By copying and pasting the div class code you can have the amount of rows you require.
As recommended, copying and pasting each piece of code individually, changing the data between the tags, then previewing will help you understand better how columns are built.
I hope you find this training helpful in understanding how you can build columns without plugins, using tables, or changing your style sheet. If you have any questions or need any further help, please don't hesitate to contact me
If you find this training helpful, a like and/or comment would be much appreciated. Thank you.
I just looked at this training and it looks way over my head as you predicted, but that may be because I have not looked at the "creating a HTML grid" training yet. So I'll look at that and then come back to this. Thanks!
~ Rae Anne