docs: Mention that all the sysext steps should be done in an empty dir

diff --git a/docs/sysext.md b/docs/sysext.md
index 99d27724169a98c9f939dc2146658c2dc1167efe..045e10c484b37ec8bfc8c36a59c8e7dfb7e6ef12 100644 (file)
--- a/docs/sysext.md
+++ b/docs/sysext.md
@@ -11,8 +11,8 @@ To keep things manageable, we'll use mkosi's support for building
 multiple images so that we can build our base image and system extension
 in one go.
 
-Let's start by defining a base configuration file `mkosi.conf` with some
-shared settings:
+Start by creating a temporary directory with a base configuration file
+`mkosi.conf` with some shared settings:
 
 ```conf
 [Output]
@@ -20,6 +20,9 @@ OutputDirectory=mkosi.output
 CacheDirectory=mkosi.cache
 ```
 
+From now on we'll assume all steps are executed inside the temporary
+directory.
+
 Now let's continue with the base image definition by writing the
 following to `mkosi.images/base/mkosi.conf`: