diff --git a/backend/application/src/video/service.rs b/backend/application/src/video/service.rs
index 4ccebc9..8f5c200 100644
--- a/backend/application/src/video/service.rs
+++ b/backend/application/src/video/service.rs
@@ -5,7 +5,7 @@ use std::io::{BufRead, BufReader};
 use std::path::Path;
 use std::io::Read;
 use lumiere_domain::video::error::VideoError;
-use lumiere_domain::video::model::library_item::LibraryItem;
+use lumiere_domain::video::model::library_item::{LibraryItem, ReadLibraryItem};
 use lumiere_domain::video::port::VideoPort;
 
 #[derive(Clone)]
@@ -19,15 +19,12 @@ impl VideoService {
     }
 
     pub fn list_root_folder(self) -> Result<Vec<LibraryItem>, VideoError> {
-        let library_items = self.video_port.list_root_folder()?;
-
-        let items_without_id = library_items.iter().filter(|item| item.id == None);
-        // generate a new Uuid for each item without id
-        // assign this new Uuid to the item
-        // save the item by using the method video_port.save
-        // replace the items_without_id by modified items_without_id
-
-        Ok(vec!())
+        let read_items_with_possibly_no_id = self.video_port.list_root_folder()?;
+        let items_with_id = read_items_with_possibly_no_id.iter()
+            .map(ReadLibraryItem::map_to_library_item)
+            .collect();
+        self.video_port.save_all(items_with_id);
+        Ok(items_with_id)
     }
 }
 
diff --git a/backend/domain/src/video/model/library_item.rs b/backend/domain/src/video/model/library_item.rs
index 63f4ddb..b272393 100644
--- a/backend/domain/src/video/model/library_item.rs
+++ b/backend/domain/src/video/model/library_item.rs
@@ -1,3 +1,4 @@
+use std::io::Read;
 use uuid::Uuid;
 
 pub enum LibraryItemType {
@@ -15,4 +16,13 @@ pub struct ReadLibraryItem {
     pub id: Option<Uuid>,
     pub name: String,
     pub r#type: LibraryItemType,
+}
+impl ReadLibraryItem {
+    pub fn map_to_library_item(&self) -> LibraryItem {
+        LibraryItem {
+            id: self.id.unwrap_or(Uuid::new_v4()),
+            name: self.name,
+            r#type: self.r#type,
+        }
+    }
 }
\ No newline at end of file
diff --git a/backend/domain/src/video/port.rs b/backend/domain/src/video/port.rs
index d78bfcb..5af453c 100644
--- a/backend/domain/src/video/port.rs
+++ b/backend/domain/src/video/port.rs
@@ -7,7 +7,7 @@ pub trait VideoPort: Send + Sync {
     fn list_root_folder(&self) -> Result<Vec<ReadLibraryItem>, VideoError>;
     fn list_folder(&self, folder_id: Uuid) -> Result<Vec<ReadLibraryItem>, VideoError>;
     fn get_video_stream(&self, video_id: Uuid) -> Result<Video, VideoError>;
-    fn save(&self, library_item: LibraryItem) -> Result<(), VideoError>;
+    fn save(&self, library_item: &LibraryItem) -> Result<(), VideoError>;
     fn clone_box(&self) -> Box<dyn VideoPort>;
 }
 
diff --git a/backend/infrastructure/src/video/adapter.rs b/backend/infrastructure/src/video/adapter.rs
new file mode 100644
index 0000000..5eb05d1
--- /dev/null
+++ b/backend/infrastructure/src/video/adapter.rs
@@ -0,0 +1,55 @@
+use lumiere_domain::video::error::VideoError;
+use lumiere_domain::video::model::library_item::{LibraryItem, ReadLibraryItem};
+use lumiere_domain::video::model::video::Video;
+use lumiere_domain::video::port::VideoPort;
+use uuid::Uuid;
+
+pub struct VideoAdapter {
+
+}
+
+impl VideoAdapter {
+    pub fn new() -> Self {
+        Self {}
+    }
+
+    pub fn get_root_folder_read_library_items(&self) -> Result<Vec<ReadLibraryItem>, VideoError> {
+        // get the root_folder path from the environment variable named "ROOT_FOLDER"
+        // list all elements inside this folder on the file system
+        // map all those elements into ReadLibraryItem objects
+        // return the list
+        todo!()
+    }
+
+    pub fn get_all_library_items_from_db(&self) -> Result<Vec<ReadLibraryItem>, VideoError> {
+        todo!()
+    }
+}
+
+impl VideoPort for VideoAdapter {
+    fn list_root_folder(&self) -> Result<Vec<ReadLibraryItem>, VideoError> {
+        // In parallel:
+        //  - call method "get_root_folder_read_library_items()"
+        //  - call method "get_all_library_items_from_db()"
+        //
+        // then, merge the two lists. If an item from the "get_root_folder_read_library_items()" result has the same id as an item from the "get_all_library_items_from_db()" results, merge those two items in one single.
+        // return the merged list
+        todo!()
+    }
+
+    fn list_folder(&self, folder_id: Uuid) -> Result<Vec<ReadLibraryItem>, VideoError> {
+        todo!()
+    }
+
+    fn get_video_stream(&self, video_id: Uuid) -> Result<Video, VideoError> {
+        todo!()
+    }
+
+    fn save(&self, library_item: LibraryItem) -> Result<(), VideoError> {
+        todo!()
+    }
+
+    fn clone_box(&self) -> Box<dyn VideoPort> {
+        todo!()
+    }
+}
\ No newline at end of file
diff --git a/backend/infrastructure/src/video/mod.rs b/backend/infrastructure/src/video/mod.rs
index cf6b588..bb40162 100644
--- a/backend/infrastructure/src/video/mod.rs
+++ b/backend/infrastructure/src/video/mod.rs
@@ -1,2 +1,3 @@
+pub mod adapter;
 pub mod model;
 pub mod video_format_detector;
\ No newline at end of file
diff --git a/backend/infrastructure/src/video/video_format_detector.rs b/backend/infrastructure/src/video/video_format_detector.rs
index 2d9b9c4..3ba723c 100644
--- a/backend/infrastructure/src/video/video_format_detector.rs
+++ b/backend/infrastructure/src/video/video_format_detector.rs
@@ -1,7 +1,7 @@
 use std::fs::File;
 use std::path::Path;
-use lumiere_domain::video::library_item::VideoFormat;
-use lumiere_domain::video::library_item::VideoFormat::{AVI, MKV, MP4, UNKNOWN, WEBM};
+use lumiere_domain::video::model::video::VideoFormat;
+use lumiere_domain::video::model::video::VideoFormat::{AVI, MKV, MP4, UNKNOWN, WEBM};
 
 /// Determine Content-Type by reading file headers (magic numbers)
 pub fn get_content_type(path: &Path) -> VideoFormat {