Hi Bob C,
Thanks for contacting us, to fix your indentation issue, you can try one or more of the following steps:
Apply a consistent style to all your paragraphs, except the first paragraph in each chapter. You can do this by selecting all your paragraphs and choosing a style from the Style group on the Home tab of the ribbon. You can also create a new style or modify an existing style to suit your preferences. https://support.microsoft.com/en-us/office/indent-the-first-line-of-a-paragraph-b3721167-e1c8-40c3-8a97-3f046fc72d6d
Remove any manual indentation from your paragraphs, except the first paragraph in each chapter. You can do this by selecting all your paragraphs and clicking on the Decrease Indent button on the Home tab of the ribbon until there is no indentation left. You can also use the Paragraph dialog box to set the indentation to zero for all your paragraphs https://support.microsoft.com/en-us/office/adjust-indents-and-spacing-in-word-dd821599-b731-4c29-be3c-d854a705e086.
Remove any tab characters from your paragraphs, except the first paragraph in each chapter. You can do this by selecting all your paragraphs and pressing Ctrl+H to open the Find and Replace dialog box. In the Find what box, type ^t (this represents a tab character). In the Replace with box, leave it blank. Click on Replace All to remove all tab characters from your paragraphs.
I hope these steps help you adjust the indent of the first line of paragraph in your long word document.
Warm Regards,
Sola.