-minor intro

-jeton 4gb not supported

book/opmanual_duckiebot/atoms_17_operation_manual_duckiebot/1_5_hw_assembly_db21m.md

@@ -22,14 +22,18 @@ Result: An assembled Duckiebot in configuration `DB21M`.
 
 <!--
 -->
-These instructions are your friend. Follow them carefully, especially if it's the first time you assemble a `DB21M`. Small variations might cause big effects (e.g., don't flip your cables around!).
+## Foreword
+
+These instructions are your friend. Follow them carefully, especially if it's the first time you assemble a `DB21M`. Small variations might cause big effects (e.g., don't flip your cables!).
+
+## Overview
+
+A Duckiebox contains the following components:
 
 <div figure-id="fig:db21m-parts-overview" figure-caption="Overview of all parts in your Duckiebox">
      <img src="db21-parts-overview.jpg" style='width: 40em' />
 </div>
 
-Note: The current `DB21M` software supports only NVIDIA Jetson Nano 2GB, not 4GB.
-
 The assembly process is divided in 9 parts. They must be completed in the following order:
 
 - [Part 1: Preliminary Steps](#howto-preliminary-db21m)
@@ -44,21 +48,26 @@ The assembly process is divided in 9 parts. They must be completed in the follow
 
 - [FAQ](#op-faq-db21m)
 
-The FAQ section at the bottom of this page might be the first thing to visit if something is not clear. This may already answer your comments, questions or doubts.
+The FAQ section at the bottom of this page provides resolutions to common symptoms.
 
 ## Preliminary Steps {#howto-preliminary-db21m}
 
 ### Unboxing
-Unbox all of your components and lay them out on a flat surface. Ensure that you have well lit, uncluttered space to work on. Do not show any violence to the Duckiebot pieces or they might break.
 
-Note: Your Duckiebot chassis are under the white protection foam. To get your Duckiebot chassis, pull out the white protection foam in the box after remove everything.
+Unbox all of your components and lay them out on a flat surface. Ensure that you have well lit, uncluttered space to work on.
 
-Although not necessary, a small (M2.5) wrench will ease some of the next passages.
+Note: "The Duckiebox hides but does not steal". Your Duckiebot chassis is under the white protection foam. To get to the chassis, pull out the white foam from the box after removing everything. Mind that the upper part of the inside foam has several side pockets in addition to a main compartment where components are located.
+
+Although not necessary, a small (M2.5) wrench might ease some of the next passages.
+
+Note: we currently support the NVIDIA Jetson Nano 2GB developer kit, not 4GB. 
 
 ### Plastic cover
+
 Peel the plastic cover from all the chassis parts on both sides.
 
 ### Screws, Nuts and Stand-offs
+
 Each type of screw, nut and stand-off is labeled with an index. You will find corresponding labels on the pictures at each step. Using the right parts at each step will prevent undesirable effects (e.g., nylon screws prevent electrical shorts).
 
 <div figure-id="fig:db21m-parts_indices" figure-caption="Overview of interlocking parts">