doc: Add description for linking module

1 files changed, 23 insertions, 2 deletions

diff --git a/doc/src/04020-module-link.md b/doc/src/04020-module-link.md
index 95e6a334..4775d25a 100644
--- a/doc/src/04020-module-link.md
+++ b/doc/src/04020-module-link.md
@@ -4,9 +4,30 @@ The Linking module.
 
 ### Description
 
-<!-- Description of the module -->
+The linking module `imag-link` is one of the plumbing modules.
+It offers the possibility to link entries in the store.
+
+It also offers the functionality to link to external sources. This functionality
+_can_ be used to link to external URLs, but the bookmarking module should be
+used to do this (see @sec:modules:bookmarks).
+
+The linking module offers functionality to add, remove and list both internal
+(store entry to store entry) and external (store entry to URL) links.
+
+#### Internal linking
+
+<!-- internal linking description remains to be written -->
+
+#### External linking
+
+A store entry can only have _one_ external link. Therefor, when you create an
+external link, the linking module creates a new entry in the store which links
+to this URL. The linking module then links you entry with this new entry by
+using an internal link. This way one entry can have multiple external links
+attached to it and external links are deduplicated automatically.
 
 ### Backends
 
-<!-- Backends the module supports including links to external resources -->
+As this is a plumbing module and only intended to be used with the imag store,
+there is no reason to have other backends.