To create simple numbered lists you basically just need to select the tool in the Write Ribbon and start typing – or just select the paragraphs you want to turn into a list and then select the tool.
To change the text and paragraph formatting of the list contents you need to apply a style or format the paragraph and text manually. For details see Formatting lists.
The only thing that is a little tricky at first is inserting un-numbered items within list while maintaining the automatic list numbering. It's easy once you know how – see the instructions below for details!