To the left you see a vertical navigation bar with a TOC: Table Of Contents. Uppermost is a link to return to the Sailor Logbook Homepage, followed by a link to a Search function.
Hereafter comes a list of links to various help pages (chapters). A help page is opened by clicking / tapping:
When a help page is opened, its entry in the TOC is highligthed. Scroll the TOC if it's longer than your screen height.
The help pages are shown in one and same browser window (this), i.e. clicking / tapping links usually opens pages in the same window.
In contrast to this, clicking / tapping an external link - which has this color - opens a new window or tab.
The manual has many cross references - links forth and back - but be prepared to also use the browser commands Back (PC/Mac: Alt+left arrow) and Forward (PC/Mac: Alt+right arrow) often, to browse the history.
Many pages have screendumps of App pages - relating to the content. Most of them are taken on an iPhone SE (4" screen). Please abstract from this - of course the App scales to fit larger screens as well.
Finally, to help you navigate extensive chapters, these have a local TOC with links to individual sections.
Sailor Logbook S App manual - © Copyright 2018 CoaSoft ApS Denmark