Format Bengali Book for KDP

I have a complete Bengali manuscript sitting in a Word document and I now need a clean, print-ready interior for Amazon KDP. Everything is text only—no illustrations—so the main focus is flawless Bengali typesetting and rock-solid page layout.

Here is what I’m looking for:
• Convert the Word file into a print-ready PDF that passes KDP’s previewer on the first try.
• Advise me on the most suitable trim size (I’m undecided between the common 6"×9", 5"×8", or 8.5"×11"). Once we agree, set up correct margins, gutter, headers/footers, and page numbers.
• Check every line of Bangla text to be sure vowel signs, conjuncts, punctuation, and line breaks appear naturally—no awkward spacing or mis-positioned glyphs.
• Provide the final PDF plus the working file you use (InDesign, Affinity Publisher, or a cleanly styled Word template) so I can make minor edits later if needed.

Acceptance criteria: the file must upload without errors, render perfectly in KDP’s Print Preview, and show no typographic issues when printed.

If you routinely format Bangla titles for print, this should be straightforward. Let me know roughly how many days you need and any questions you have about the manuscript length or style decisions.