[problem] Improve slides.

slides/problem.md

@@ -4,6 +4,10 @@ title: DuMu^x^ applications
 
 # Example application
 
+## Simulation goal
+
+<img style="float: right;" src="../exercises/extradoc/exercise1_setup.png">
+
 ## Gas injection / immiscible two phase flow
 
 Mass balance equations for two fluid phases:
@@ -369,6 +373,7 @@ See [Part I: Runtime parameters](./params.html) for details.
 ## Main program
 
 * Each problem has one main file (`test_name.cc` or `main.cc`)
+* Here: `2pmain.cc` and `2p2cmain.cc`
 * Contains the `main` function (mandatory in C/C++ programs)
 
 ## Main function
@@ -660,6 +665,11 @@ But you can of course "install" Dune modules and DuMu^x^.
 
 ## Build system - dunecontrol
 
+* For Dune, CMake is triggered via the `dunecontrol` script
+
+```sh
+./dune-common/bin/dunecontrol [options] <command>
+```
 * useful options:
   - `--opts=<optionfile.opts>` specify e.g. compiler flags; DuMu^x^ provides [`dumux/cmake.opts`](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/cmake.opts).
   - `--build-dir=<build directory>` specify path for out-of-source build; Default: every module contains its own build directory called `build-cmake/`
@@ -688,20 +698,17 @@ removes the `CMake` cache files from all Dune modules.
 
 ## Build system
 
-`CMakeLists.txt` for an example application: create a test target `test_2p_incompressible_box`
-by defining name, source file and command line arguments:
+`CMakeLists.txt` for an example application: create a test target `exercise_basic_2p`
+by defining a name and source file:
 
 ```cmake
-dumux_add_test(
-    NAME test_2p_incompressible_box
-    SOURCES test_2p_fv.cc
-    CMD_ARGS test_2p.input
-)
+dumux_add_test(NAME exercise_basic_2p
+               SOURCES 2pmain.cc)
 ```
 
 ## Build system
 
-Add extra compile definitions and commands (typical
+Another example: add extra compile definitions and commands (typical
 for DuMu^x^ regression tests):
 
 ```cmake