To use libreoffice writer type what you wish to type into the main part of the window. If you wish to save your data press the icon that looks like a floppy disk or press control + s. To open a previously saved document press the button that looks like a folder or press control plus o. To load or save a file from the menu file -> open to open a file or file -> save. To have save your file as a pdf press the button that is a sheet of paper with curved red lines on it or go file -> export and select the file type as pdf.
To change the font size There is a drop down box with a number in it you can type the font size you want in this box or select from the dropdown menu. You can change the font with the drop down box to the left of the font size which you can type and it autocompletes the fonts or select from the drop down menu. To make your text bold you can select the text with the mouse and press the button that looks like **B** or press control + B. To make the font italic press the button that looks like *I* or press control + I after selecting the text or keep typing with it to be italic. To make strikethrough press the button that is a s with a line through it.
To make text superscript press the button with A and a smaller B located above it as if it in superscript. To make text subscript press the button that is an A with a smaller B located slightly below it.
To check the spelling of your document press the ABC button with a checkmark, from the menu -> tools spelling or press f7. After you are done writing your document you can press the button that looks like a printer to print, press control+ p or file -> print. To view your word count of how many words are currently in the document is with nothing slected at the bottom of the libreoffice writer window. If you select text with the mouse you can also see the word count of selection from the same spot.
To insert special symbols or characters press the button with the Ω symbol or from the menu Insert -> Special character. To insert a page break press control + enter or from the menu Insert -> Page Break.
To undo a mistake you make press control + z or press the yellow arrow pointing to the left. If you accidently undid code redo or press the green arrow pointing to the right.
To center your text is press the button with the horizontal lines centered or format -> align-> centered. To have your text justified to the right press the button with the lines on the right or format -> align -> right. To have your text aligned to left press the lines on the eleft with or format -> align -> left. To center justify your text which will add spaces in between words to make it appears at both orders press the button that has solid horizontal lines all of eqaul length to center justify the text.
