diff --git a/src/cmus/mod.rs b/src/cmus/mod.rs
index 516d93b..c0a67b4 100644
--- a/src/cmus/mod.rs
+++ b/src/cmus/mod.rs
@@ -15,6 +15,9 @@ use typed_builder::TypedBuilder;
 
 pub trait TemplateProcessor {
     fn process(&self, template: &String) -> String;
+
+    /// Returns a vector of keys found in the template.
+    /// The keys are the strings between curly braces.
     fn get_keys(template: &String) -> Vec<String> {
         let mut keys = Vec::new(); // Just a buffer to store the keys.
         let mut key = String::new(); // Just a buffer to build the key.
@@ -85,6 +88,9 @@ pub enum CmusError {
 }
 
 impl TemplateProcessor for Track {
+    /// Process the template with the track metadata.
+    /// The template is a string with placeholders that will be replaced with the track metadata.
+    /// The unknown placeholders will be skipped (don't replaced with anything, because they are maybe placeholders for player settings).
     fn process(&self, template: &String) -> String {
         #[cfg(feature = "debug")]
         {
diff --git a/src/cmus/player_settings.rs b/src/cmus/player_settings.rs
index 9aa6556..41efce4 100644
--- a/src/cmus/player_settings.rs
+++ b/src/cmus/player_settings.rs
@@ -38,6 +38,9 @@ pub enum AAAMode {
 }
 
 impl TemplateProcessor for PlayerSettings {
+    /// Replace all keys in the template with the corresponding values.
+    /// If the key is unknown, it will be replaced with an empty string.
+    /// This function should be used after the track metadata placeholders have been replaced.
     fn process(&self, template: &String) -> String {
         #[cfg(feature = "debug")]
         {
diff --git a/src/cmus/query.rs b/src/cmus/query.rs
index e66b8d2..5288cb1 100644
--- a/src/cmus/query.rs
+++ b/src/cmus/query.rs
@@ -44,6 +44,7 @@ impl CmusQueryResponse {
         PlayerSettings::from_str(&self.player_settings_row)
     }
 
+    /// Compare this response with another one, and return the events that happened.
     pub fn events(&self, other: &Self) -> Result<Vec<CmusEvent>, CmusError> {
         #[cfg(feature = "debug")]
         info!("Comparing cmus responses: {:?} and {:?}", self, other);