The idea behind LO Writer is not WYSIWYG in the end. If it were, it would miss its goal which is to automate as much as possible the process of writing and formatting.
Automation is based on styles so that you only need to set a paragraph style (and character styles for what is different inside a paragraph) to get all you formatting and layout.
This requires some planning to enumerate the needed styles. Then you configure (= customize to your specific needs) the Writer application through a dictionary of styles and you save this dictionary into a “template”. Afterwards, you open every new document from the template and it inherits your styles dictionary.
Working WYSIWYG (if you’re talking about text formatting) – using toolbar button and keyboard shortcuts – is a very bad idea because it turns document edition and maintenance into a real nightmare. With styles, you only tune your styles and the whole document is updated without the need to track every formatting instance.
Read the Writer Guide for an initiation to styles and practice a bit on scratch documents.