Update acsl-importer.md

_fc-plugins/acsl-importer.md

@@ -8,15 +8,35 @@ distrib_mode: proprietary
 
 ## Overview
 
-This plug-in adds to Frama-C support for out of C source files ACSL specification. Therefore
-it is useful only to people that intend to write ACSL specifications and do not want to write
-them inside comments of the C source files.
+The plug-in allows to import external ACSL specifications written in files, 
+separated from the C source files. 
+That provides more flexibility in the use of ACSL in the life cycle of
+software since the merge between the specifications and the source code is
+done by the plug-in. 
 
 In addition, the plug-in allows to enter ACSL annotations directly via the Graphical User
 Interface.
 
+Therefore `ACSL Importer` plug-in is useful only to people that intend to write
+ACSL specifications and do not want to write them inside comments of the C source files.
+
+
 ## Usage
 
+The use of the plug-in could be the following, except if the given options lead
+to run analysis (analysis should be launched through the graphical interface):
+
+- `frama-c-gui <importing options> <C files>`
+
+Otherwise, options have to be splitted into two groups and given as follow:
+
+- `frama-c-gui <importing options> <C files> -then <analysis options>`
+
+Once the plugin installed, the next command gives the up-to-date list of the
+ plug-in options:
+
+- `frama-c -acsl-importer-help`
+
 All options of the plug-in are prefixed by `-acsl-`.
 
 The main options are:
@@ -39,6 +59,8 @@ The main options are:
   pretty prints a text containing the version ID of the plugin.
 
 
+## Example
+
 The plug-in can be used as follows. From a C file:
 
 ```c
@@ -87,7 +109,7 @@ function job:
 The following command line:
 
 ```
-frama -c -acsl-import demo.acsl demo.c -print -no-unicode
+frama-c -acsl-import demo.acsl demo.c -print -no-unicode
 ```
 
 generates the following output: