addet program structure

documentation/program_structure.md

@@ -0,0 +1,22 @@
+# Downloading
+
+## Query
+
+- parsing query into music objects
+
+# Pages
+
+## from music objects to query
+
+```
+song: artist1, artist2
+
+1. artist1 - song
+2. artist2 - song
+```
+
+```
+artist: song1, song2
+
+1. artist
+```