As @ratrace said, try F1 to access Help. You can also type “how to use libreoffice” into your browser search box to see a plethora of articles ranging from “Getting Started with LibreOffice 4.0” (by The Document Foundation), to “Taming LibreOffice,” to “Instructions for Using LibreOffice Calc” (a wiki via LibreOffice.org).
From you comments, I’m not quite sure what you mean by “Spreadsheet columns cannot be expanded to create a header…” A spreadsheet document header can be accessed and customized from Format > Page by clicking the Header tab.
If you are referring to freezing rows to create a static column heading while the detail scrolls, select View > Freeze Rows and Columns. This will freeze rows to the left of your cursor and freeze columns above your cursor.
The “formulas for SUM and Multiply” are basically the same as in Excel. The equal sign (=) entered as the first character in a formula indicates a mathematical operation. “=SUM([From]:[To])” adds the cells for the range specified. Multiplying cells uses the asterisk (*) symbol to indicate a multiplication operation.
I hope this helps.
Please click the check mark next to the post you believe best answers your question.