How to insert a simple header and page numbers.

I’m an engineering student and writing is not my thing, so I apologize if this is supposed to be obvious. But I’m about to throw something at my screen because of how frustrating this is, when it should be so simple.

All I want is a a multiline header on the top left of only the first page and a page number on the top right.

On subsequent pages, just the page number on the right corner.

I tried going to Insert > Header and Footer > Header > Default Style (Default Style was the only option here) but whatever I typed appeared on all pages. I went to Google but could only find five year old questions. Then, as per the built-in help pages, I went to Format > Page and under the Next Style: dropdown I picked First Page then clicked Apply > OK. Finally thinking I got it fixed, I went to Insert > Header and Footer > Header > First Page … and … it inserts on the second page no matter what I do.

Help would be appreciated. Thanks for your patience.

I think the simplest way of getting what you described will be to modify the “page style” you ae using for your document (whether you know it or not).

To do this open the styles list by selecting View>Styles. Open the list of page styles by clicking on the fourth icon from the left in the row above the list (its name will appear if you hover the mouse pointer above it). The style you are using (probably Default) will be highlighted. Right-click on this and select Modify in the small dialogue that will open.

A larger dialogue box will open where you can set up the page style used for your document. Select Header. Set to “Header on” and “Same content on left and right pages”. Do not tick “same content on first page”

Click in the first page header are to shift the cursor there and insert your multi-line header on the left.

Move the cursor to the right where you want the page number to appear (either by inserting a row of spaces, which some will disapprove of, or by using a right tab which does the job better). Select Insert>Fields>Page Number. The page number should appear, but if you get some text select View>Field Names to toggle between the name of the field and its effect.

Insert some blank lines to create your second page which should have an empty header. Put the cursor at right of the header and insert another page number field as before. The page number will appear on all the following pages.

I suggest reading up on styles and their use in the LibreOffice user manuals because used properly they save a lot of time when producing long documents. And you can get a lot of useful variations (e.g. have your odd and even page numbers appear on different sides of the page for double sided printing). You an download the manuals, free of charge, as PDFs from the LO website.

See [Tutorial] Page styles and headers/footers (View topic) • Apache OpenOffice Community Forum

And this one:
https://forum.openoffice.org/en/forum/viewtopic.php?f=71&t=1221