This seems to be a different question though related to it. IMHO, it is better to ask a new question (with all necessary details as you did) with a reference (a link) to this question. Thus, you’ll have more relevant answers and comments and contributors won’t need to scroll down to find your topic.
No. This is not the best way to do it but it does not mess the file. Schematically, when you format a document, you have three layers (this is over-simplified):
- paragraph style at deepest level,
- character style (which overrides paragraph style default character properties),
- direct or formatting (which overrides both paragraph and character styles properties) at shallowest level.
Direct formatting is everything you modify with keyboard shortcuts, toolbar buttons or mouse drags. This is the first step of your own procedure.
When you request to modify Body Text, you transfer direct formatting (DF) from the current selection into the paragraph style, thus removing DF. But, beware! if you have inconsistent DF in your paragraph (and it is the common rule with DF) and the selection does not cover the whole paragraph, some DF may remain. In this case, your document rapidly becomes an unmanageable mess.
The “correct” procedure is to modify directly the style. There is a, Apply button to test the changes and a Reset button to revert to state when you entered the dialog.
EDIT:
Your sample file is full of direct formatting:
- no use of character styles
- no configuration of Default Paragraph Style
You seem to have chose Nimbus Sans L;Arial for your preferred font and added it over your text (but not the footnotes). You could have modified Default Paragraph Style (DPS) so that the font configured here is forwarded to all other styles (because all others inherit ultimately from DPS). - no use of list styles
You pressed a toolbar button to create your bullet lists which are still styled Body Text. Usually, list items belong in a different semantic meaning than the main discourse and therefore should have a different paragraph style.
On a 300-page document, the quantity of DF should have an important impact.