Turning off indent in first paragraph after a numbered paragraph

Are you sure those are SEPARATE paragraphs - and not forced "new lines"?

Can you turn on SHOW HIDDEN CHARACTERS and post screenshot again?

Also, switch SCREEN MODE to NORMAL.

There are a couple of possible issues here. If you had 'show hidden characters' enabled in your screen clips it might be a little easier to give you a simple answer.

From your description, it sounds as if you are using soft returns (line breaks) instead of full paragraph returns in your content. Indentation would follow your numbered paragraph style to each paragraph "segment" created below by one or more soft returns. (They are all, effectively, the same paragraph.)

To get different indentation, you need different paragraph styles. in your examples above, you should have:

• Numbered paragraph, as many as needed;
• Heading, which does not have the indentation and is probably meant to be different in format (font, spacing, etc.) as well;
• Body (or equivalent) which is the body text meant to follow the heading and be spaced, indented, etc. as desired.

It's also possible you have such styles, but your editing method created spot-override versions. In that case, you put the cursor in each paragraph and look at the list of Paragraph Styles; if there's a + appended to the style name, it's modified. Click on the paragraph name to re-apply the style. (Or right click on the style name and select "Clear [All] Overrides." Repeat all down the stack of paragraphs to make sure each has the correct, unmodified style. (There are many tools to help spot modified styles and fix them; this is the simple method.)

Does that make sense? InDesign is a wholly style-based app; you can't spot-format and 'fake it' as you do in Word and similar apps. Mastering paragraph and character styles is essential; mastering object, table and cell styles after that is very useful.