[rosewood]

Thank you Ducks. But I am finding it hard to translate your reply to plain English.
Am I right with this interpretation:

1. Separate the Chapter headings and put them on top of the plaintext file in the correct order

2. Add h tags to them and put this block right on top of the textfile thus (string_n is the chapter descriptor for chapter n):

<h1> Chapter 1 string1 </h1>
<h1> Chapter 2 string2 </h1>
<h1> Chapter 3 string3 </h1>


Chapter 1 string1
The quick brown fox jumped over the lazy dog. And so on.......

----------------the rest of the text file---------------------------

3. Untick the force ToC generation box in the Conversion > TOC section

Will the converter automatically link the Chapter entries at the top of the file to their corresponding locations in the endproduct azw3 file?