Here is a post where some indispensable plugins are brought up: https://forum.dokuwiki.org/d/18131-hello-there
Regarding chapter names and table of contents, there are many ways to achieve what you need. In DokuWiki's config you can switch "useheading" to Navigation, so the first heading will be used instead of file and folder names for your navigation purposes. I've had mixed results using the simplenavi plugin on Hogfather, but that's a simple one for listing pages in a namespace (ie. chapter names?).
For sidebar, just edit the sidebar page (sidebar.txt) and insert whatever links or plugin syntax you like, eg. simplenavi. Once you get warmed up to DokuWiki, there is no better software for documentation building, or wikis for that sake.
Table of contents: surely you know that DokuWiki makes an automatic ToC after you add a certain amount of headings to any page. So I suppose the ToC you are talking about is on a front page or similar. Why don't you try to explain with some concrete examples of what you want to achieve, and the community can chime in with concrete answers.
I hope you will be successful in your endeavours, and welcome to the DokuWiki forums!