getting_started.md: Did some restructuring

docs/documentation/sizing/tank_design/getting_started.md

@@ -45,18 +45,6 @@ To single execute the _tank\_design_ module, we need an _acXML_ file that alread
 - _fuselage\_design_
 - _mission\_analysis_ <sup>*</sup>
 
-<sup>*</sup> The _tank\_design_ execution is also possible without mission analysis data. Alternatively, the following assumption is used to calculate the mission fuel amount:
-
-$$
-    m_{\text{fuel}} = n_{\text{PAX}} \cdot R \cdot \frac{E}{100 \text{ km}}
-$$
-
-In which
-
-- $n_{\text{PAX}}$ - number of passengers
-- $R$ - range in km
-- $E$  - energy demand (3.35 liter per PAX per 100 km)
-
 The following data should then be available in the _acXML_:
 
 1. Requirements and specifications
@@ -75,6 +63,20 @@ The following data should then be available in the _acXML_:
 !!! note 
     When the UNICADO workflow is executed the tool is run automatically. In this case, all the required data should be available anyway.
 
+<sup>*</sup> The _tank\_design_ execution is also possible without mission analysis data. Alternatively, the following assumption is used to calculate the mission fuel amount:
+
+$$
+    m_{\text{fuel}} = n_{\text{PAX}} \cdot R \cdot \frac{E}{100 \text{ km}}
+$$
+
+In which
+
+- $n_{\text{PAX}}$ - number of passengers
+- $R$ - range in km
+- $E$  - energy demand (3.35 liter per PAX per 100 km)
+
+Using the volumetric energy density of kerosene, the initial energy demand can then be calculated.
+
 ## Configuring tank design parameters in the aircraft exchange file {#configuring-tank-design-parameters-in-the-aircraft-exchange-file}
 The desired tank configuration is defined by the user in the aircraft exchange file. The information can be found in the `aircraft_exchange_file/requirements_and_specifications/design_specification/configuration/tank_definition` block.