Format settings to be set up before writing? or after?

When I began writing my book, I formatted font, size of for body, indents, spacing, etc… only to find that I have had to repeatedly reset the settings.
I’ve tried finding definite directions in the manual, but have to say, the manual is a massive, techy, badly indexed supposedly directional and informative “manual.” So, I’d like to know how set up formatting defaults for current project…and should that be done before or after the writing?
Thanks, Old Lady with hair on fire!

For these sorts of basic formatting choices, Scrivener distinguishes between i) the default formatting you see in the Editor pane when you are writing, and ii) the formatting choices you want to see when you /compile/ your manuscript (into whatever form you do). These two things need not be at all the same, and many writers take advantage of this feature of Scrivener. You can compile your draft “as-is” though if you wish.

You can set default paragraph formatting in Scriv preferences. Doing so will not change the appearance of existing paragraphs, but will effect new paragraphs made in newly created docs in your project. For existing paragraphs, there is an option in the Format menu to apply the (new) default paragraph format to a selection of paragraphs.

To effect the styling of basic paragraphs at /Compile time/, you should see if a provided compile format already does what you want. If not, you can duplicate and edit any of these compile formats in order to tweak the basic formatting to be applied to your text at compile time.