Improve Custom Logs documentation (#5153)

Now it describes detailed steps how to set it up.

Author: rdner

packages/log/changelog.yml

@@ -1,4 +1,9 @@
 # newer versions go on top
+- version: "1.1.1"
+  changes:
+    - description: Improve documentation
+      type: enhancement
+      link: https://github.com/elastic/integrations/pull/5153
 - version: "1.1.0"
   changes:
     - description: Add custom logs and processors

packages/log/docs/README.md

@@ -1,3 +1,12 @@
-# Log Package
+# Custom Logs Package
 
-The log package is used as a generic package based on which any log file can be tailed by adjusting the ingest pipeline.
+The Custom Logs package is used for ingesting arbitrary log files and manipulating their content/lines by using Ingest Pipelines configuration.
+
+In order to use the package, please follow these steps:
+
+1. [Setup / Install Elastic Agent](https://www.elastic.co/guide/en/fleet/current/install-fleet-managed-elastic-agent.html) at the machine where the logs should be collected from
+2. Identify the log location at that machine e.g. `/tmp/custom.log`. Note that `/var/log/*.log` is fully ingested by the [System](https://docs.elastic.co/en/integrations/system), no need to add this path if the [System](https://docs.elastic.co/en/integrations/system) integration is already used
+3. Enroll Custom Logs integration and add it to the installed agent. Give the dataset a name that fits to the log purpose, e.g. `python` for logs from a Python app. Make sure to configure the path from the step 2
+4. Check that the raw log data is coming in via [Discover](https://www.elastic.co/guide/en/kibana/current/discover.html) by filtering the `logs-*` indices to the dataset name given in step 3, e.g. `logs-python`
+5. Configure the parsing rules via [Ingest Pipelines](https://www.elastic.co/guide/en/elasticsearch/reference/current/ingest.html), e.g. JSON Parsing or [grok](https://www.elastic.co/blog/slow-and-steady-how-to-build-custom-grok-patterns-incrementally) parsing
+6. Create a [custom dashboard](https://www.elastic.co/guide/en/kibana/current/create-a-dashboard-of-panels-with-web-server-data.html) that analyzes the incoming log data for your needs

packages/log/manifest.yml

@@ -4,7 +4,7 @@ title: Custom Logs
 description: >-
   Collect custom logs with Elastic Agent.
 type: integration
-version: 1.1.0
+version: 1.1.1
 release: ga
 license: basic
 categories: