diff --git a/docker.md b/docker.md
index 1a251f4..6182c37 100644
--- a/docker.md
+++ b/docker.md
@@ -4,7 +4,19 @@ Assume you use Archlinux.
 
 Read [Docker](https://wiki.archlinux.org/index.php/Docker).
 
-After install docker, add your user to `docker` group.
+Start/enable service:
+
+```sh
+systemctl start docker.service
+
+systemctl enable docker.service
+```
+
+Add your user to `docker` group:
+
+```sh
+sudo usermod -aG docker $USER
+```
 
 Delete all images, containers, volumes, and networks that are not associated with a container (dangling):
 
diff --git a/kafka.md b/kafka.md
index d8091f8..4939046 100644
--- a/kafka.md
+++ b/kafka.md
@@ -4,7 +4,9 @@ Assume you use Archlinux.
 
 Read [Apache Kafka](https://wiki.archlinux.org/index.php/Apache_Kafka).
 
-After install `kafka`, `zookeeper`, start service:
+Install [kafka](https://aur.archlinux.org/packages/kafka/), [zookeeper](https://aur.archlinux.org/packages/zookeeper/).
+
+Start service:
 
 ```sh
 systemctl start kafka.service
diff --git a/redis.md b/redis.md
index 721a906..243ab9b 100644
--- a/redis.md
+++ b/redis.md
@@ -4,7 +4,7 @@ Assume you use Archlinux.
 
 Read [Redis](https://wiki.archlinux.org/index.php/Redis).
 
-After install `redis`, start service:
+Start service:
 
 ```sh
 systemctl start redis.service