Update app.py

app.py

@@ -268,6 +268,8 @@ if selected_app == "3) Merge CSVs":
             
     else:
         uploaded_files = st.file_uploader("Upload CSV files to merge", accept_multiple_files=True, type="csv")
+        with st.expander("Explain"):
+            st.write("Merge CSVs that contain related topics. Total CSV length should be around 50-100.")
     
         submit = st.button("Submit")
         if submit: