docs: Update the section Linkage and annotation (#802)

* docs: Update the annotation/link section + remove the section "connect your data"

* docs: Add content for the sub-section Link object

* docs: Add internal link

Co-authored-by: flaurens <flavie.laurens@unibas.ch>

docs/user-guide/data.md

@@ -27,12 +27,6 @@ N.B.: Please, note that the image, video, and audio files must be in one of the
 
 ---
 
-### Connect your data
-
-The workspace of the DSP-APP allows you to connect different resources, even if they are not in the same project (linkage), to comment on a resource and on their metadata fields (annotate). These actions will generate more data and will help to find specific resources and their relations easily.
-
----
-
 ## Search and browse
 
 DSP-APP offers the possibility for the user to search in 3 different ways: **full-text** search, **advanced** search, and **expert** search (Gravsearch query). The search bar is always available in the header of each page, whether logged in or out.
@@ -322,12 +316,22 @@ You can delete a property value. You mouse over the value and click on the delet
 
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-### Annotate and link your data
+### Annotate and link data
 
 The main feature of the flexible data storage that DSP-APP uses is the possibility to annotate and link resources and their metadata. An annotation can be a small note about a date like "Not sure about the birthdate of this person. There's another date mentioned in the resource XYZ". Inside the note, it will be possible to link to another resource.
 
 Links in DSP-APP are always bi-directional. If you link resource A with resource B, then resource B knows about this connection. If you find resource B, you have the connection to resource A as well.
 
+It is possible to link resources of the same project or from 2 different projects.
+
+DSP-APP offers two ways to link data:
+
+1. Internal linkage: it allows you to create a direct link between 2 resources. The label of the linking resource (source) will appear in the „incoming links“ section of the targeted resource. You will choose this option when you want to embed the link in a text.
+
+2. Link object:  it allows you to create an annotation (the description of the link object) that can point to one or more resources. You will prefer this option if you want the link to exist and describe it.
+
+#### Internal linkage
+
 To link 2 resources (A is an image and B is a document in the example), you go to your resource A that will be linked, open the **Share** menu and click on the button `Copy internal link on clipboard`. You have copied the internal link of your resource A that will be used to make the link with your resource B.
 
 ![Copy the internal link](../assets/images/link_copy_internal_link.png)*Copy the internal link of the resource A.*
@@ -344,6 +348,22 @@ The word (or the group of words) is now highlighted in blue-grey and is clickabl
 
 ![Link has been added to the text](../assets/images/link_saved_as_standoff.png)*The link has been added to your text.*
 
+#### Link Object
+
+To create a link object, the process starts from the search result list. You select 2 or more resources from the list and click on the button Create a link object from this selection.
+
+![Select resources to link](../assets/images/link-object-select.png)*Select the resources to link.*
+
+You fill out the form indicating the project in which you want to register the link object, as well as a label to identify it. Optionally, you can add a comment (annotation) to describe this collection of resources. Then, click on Create.
+
+![Link object form](../assets/images/link-object-form.png)*Fill in the form about the new link object.*
+
+The linked resources are listed in the `has Link to` property of the link object resource viewer. The label of your link object is searchable through a [full-text search](https://docs.dasch.swiss/latest/DSP-APP/user-guide/data/#full-text-search).
+
+![Link object resource](../assets/images/link-object-resource-view.png)
+
+It is possible to add other resources later on by clicking on the `+` button in the `has Link to` property section.
+
 ---
 
 ### Share your data