To link to another page in the documentation, use ref:
[This is a link to Configuration]({{< ref "/8/development/configuration" >}})
Rendered result:
To a link that points to a specific point in the current page, use relref:
[This is a link to the first title]({{< relref "#cross-links" >}})
Rendered result:
Internal links need to be “slugified” to work.
If you feel lost, here’s a tool that will slugify your titles.