--- a/README.md	Sun Jul 31 16:43:25 2022 +0200
+++ b/README.md	Sun Jul 31 17:54:19 2022 +0200
@@ -17,7 +17,7 @@
 
 Reference build environment is obtained by applying [provision_focal64.sh](provision_focal64.sh) on Ubuntu 20.04 amd64.
 
-## Build ##
+## Preparing source ##
 
 The top Makefile expects source code of Beremiz, Matiec and CanFestival to be 
 sibling to beremiz_public_dist directory, in the 'source directory'.
@@ -27,7 +27,7 @@
 ~/src
      /beremiz
      /beremiz_public_dist
-     /CanFestival-3
+     /canfestival
      /matiec
 ```
 
@@ -37,6 +37,8 @@
 Intermediate and final results are all placed in a single 'build directory'
 during build process.
 
+## Windows installer Build ##
+
 ### Prepare Docker image ###
 
 The script [rebuild_docker.sh](rebuild_docker.sh) is used for that purpose.
@@ -49,7 +51,7 @@
 
 ```
 #!sh
-mkdir ~/src
+mkdir ~/src ~/build
 cd ~/src
 hg clone https://hg.beremiz.org/beremiz_public_dist
 cd beremiz_public_dist
@@ -87,7 +89,7 @@
 
 Resulting installer is Beremiz-1.2.exe in 'build directory'. 
 
-## Manhole ##
+### Manhole ###
 
 Once Docker image ready, the scripts [enter_docker.sh](enter_docker.sh) and
 [enter_docker_as_root.sh](enter_docker_as_root.sh) let you issue build 
@@ -96,3 +98,26 @@
 [clean_docker_container.sh](clean_docker_container.sh) and [create_docker_container.sh](create_docker_container.sh) and 
 [clean_docker_image.sh](clean_docker_image.sh) and [build_docker_image.sh](build_docker_image.sh) are invoked by 
 [rebuild_docker.sh](rebuild_docker.sh). 
+
+## Snap Package Build ##
+
+snapcraft.yaml does not rely on HG or GIT repos, but refers to local sources, this is responsibility of caller to prepare sources for snapcraft.
+
+Reasons for this are :
+ - no parameters or conditional variables exist to tell snapcraft.yaml where to get the source from
+ - building from local source should be always possible
+ - revisions.txt must be updated in any case so that it is always possible to know what version wqas used to build resulting package
+ - when Snap is built from GitHub actions, Makefile isn't used at all, and GitHub action workflow organize sources and revisions.txt on its own.
+
+In the end, instead of just calling `snapcraft` to get a snap package, it is more complicated:
+
+```
+#!sh
+mkdir ~/src ~/build
+cd ~/src
+hg clone https://hg.beremiz.org/beremiz_public_dist
+cd ~/build
+make -f ~/src/beremiz_public_dist/Makefile DIST=snap
+
+```
+