diff --git a/Docker.md b/Docker.md
index 851fca8..d4f6029 100644
--- a/Docker.md
+++ b/Docker.md
@@ -8,10 +8,24 @@ Only amd64 currently works. Currently used Node.js 14.x segfaults at arm64 and s
 
 Dockerfile is at https://raw.githubusercontent.com/wekan/wekan/main/Dockerfile
 
-For building custom image, and then running it, uncomment these lines:
+For building custom image, and then running it, uncomment these lines,
+that are currently here, but line numbers could change, if that docker-compose.yml
+is later modified:
 
 https://github.com/wekan/wekan/blob/main/docker-compose.yml#L144-L146
 
+After your above modifications, text should look like this:
+
+```
+    #-------------------------------------------------------------------------------------
+    # ==== BUILD wekan-app DOCKER CONTAINER FROM SOURCE, if you uncomment these ====
+    # ==== and use commands: docker-compose up -d --build
+    build:
+      context: .
+      dockerfile: Dockerfile
+    #-------------------------------------------------------------------------------------
+```
+
 Then modify ROOT_URL, etc settings as needed, see https://github.com/wekan/wekan/wiki/Settings
 
 Start WeKan with custom built Dockerfile with this command: