You have a series of Heading 1 paragraphs without others in between.
The Heading n styles have property Keep with next paragraph so that a heading is never separated from its content by a page break.
In your case, the first Heading 1 is constrained to be kept with the second which is constrained with the third which is constrained with the fourth … Consequently the whole group causes the page break to occur before the first.
Things will settle by themselves as soon as you add a Text Body paragraph after your headings.
Tip: never indent paragraphs with spaces. Spaces have varying width depending on justification (because of the width of words). Learn to use paragraph styles. Each paragraph style describes the meaning of the paragraph (a heading, a list item, common text, …). A paragraph style describes the “geometric” and typographical attributes: indents, spacing, first line, alignment, font face, size and width, text flow, …
With cleverly designed styles, you no longer need to press toolbar buttons and your typing speed increases drastically.
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