diff --git a/Readme.md b/Readme.md
index 3e365de..3c1b7d9 100644
--- a/Readme.md
+++ b/Readme.md
@@ -25,15 +25,17 @@ Once you have printed all the requiered pieces as described in the [_3D printing
 
 <img src="https://git.deuxfleurs.fr/distorsion/3D-printed-parametric-40mm-gaz-mask-canister/media/branch/main/pictures/canister_asembly_step1.png?raw=true" alt="Image not available" height="300" />
 
-_Coming soon !_
+You can first put your (_covid/chirurgical_) mask or filter and put it in the _cap_ or at the top of the _sleeve_, with 0.5/1cm extra material all around the _sleeve_.
 
 <img src="https://git.deuxfleurs.fr/distorsion/3D-printed-parametric-40mm-gaz-mask-canister/media/branch/main/pictures/canister_asembly_step2.png?raw=true" alt="Image not available" height="300" />
 
-_Coming soon !_
+Secondly, you can push in the _sleeve_ within the _cap_ making sure that the whole surface of the mask/filter is fermly held and that there are no holes.
+
+You can then fill the _sleeve_ with your filter material : typicaly activated charcoal which can be source **cheaply** from activated charcoal for aquarium filter.
 
 <img src="https://git.deuxfleurs.fr/distorsion/3D-printed-parametric-40mm-gaz-mask-canister/media/branch/main/pictures/canister_asembly_step3.png?raw=true" alt="Image not available" height="300" />
 
-_Coming soon !_
+Finally you can repeat the first step with the top of the _sleeve_, putting a mask/filter, then pushing the _sleeve_/_cap_ assembly into the _main body_ before screwing the _cap_ and _main body_ together, thus securly holding the sleeve and he two mask/filter holding the filtering material in place.
 
 ## 3 - 3D printing
 
@@ -68,4 +70,8 @@ _**snap_fit_clearance** :_ \[_default=0.09mm_\] The clearance between two object
 
 ### 4.b - Geometrical parameters
 
-_Coming soon !_
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+The two most important parameters that you would probably have to tweek for your usage are :
+
+_**filter_diameter** :_ \[_default=55mm_\] interior diameter of the filter, the larger the diameter the easier breathing will be, but also the better filtering will be as air will pass more slowly through the filter for the same air flow, thus aking the filter more effective. A larger filter wil be heavier and thus be less confortable.
+
+_**filter_length** :_ \[_default=35mm_\] interior length of the filter, the longer the filter will be, the better the filter will work but also the harder it will be to breath. A longer filter wil be heavier and thus be less confortable.
\ No newline at end of file