update README

Author: asiffer

README.md

@@ -10,31 +10,42 @@ wget https://raw.githubusercontent.com/asiffer/portabledize/master/portabledize.
 
 ## Get started
 
-**Prepare your files.** You must declare the systemd service file and possibly the files you need to run your app (you may have at least an entrypoint file, like a statically compiled binary). Example:
+You need to provide two files:
+
+- The systemd service file (like `my-service.service`)
+- Extra files you want to map to the target image (you need to provide one binary at least)
+
+Here is an example with a single binary to copy.
 
 ```ini
 # files.txt
 ./my-binary /usr/bin/my-binary
 ```
 
-**Bundle it**. Give the files as input and set the name of the output file.
-
-> [!IMPORTANT]  
-> The output file will have the following format: `SERVICE_NAME.raw` where `SERVICE_NAME` is merely the name of your service file (without the `.service` extension)
+Then you can run the script.
 
-```sh
+```shell
 portabledize.sh -s my-service.service -f files.txt
 ```
 
-**Attach your service**. Then you can start it!
+It creates an image file `my-service.raw` in the current directory. You can modify the output directory with the `-d` option.
 
-```sh
-sudo portablectl attach my-service.raw
-sudo systemctl start my-service
+> [!IMPORTANT]  
+> It is important to keep this naming convention (if you provide `wtf.service`, it builds `wtf.raw`). Systemd won't accept image with filename different from service name.
+
+Finally you can attach your service anywhere (where systemd runs!).
+
+```shell
+sudo portablectl attach ./my-service.raw
+# sudo portablectl detach my-service
 ```
 
+You can look at the [./example](./example/) directory to see a true but basic sample.
+
 ## Github Action
 
+This repo follows the structure of a custom github action. So basically you can integrate `portabledize` to your CI/CD.
+
 ```yaml
 on: [push]