add feature list of the course exercises

exercises/README.md

 # DuMu<sup>x</sup> course exercises
 
-Click on the exercise to go the description
-
-* [Exercise on the basics](./exercise-basic/README.md)
-* [Exercise on the main file](./exercise-mainfile/README.md)
-* [Exercise on runtime parameters](./exercise-runtimeparams/README.md)
-* [Exercise on grids](./exercise-grids/README.md)
-* [Exercise on properties](./exercise-properties/README.md)
-* [Exercise on fluid systems](./exercise-fluidsystem/README.md)
-* [Exercise on how to create a new Dune module](./exercise-dunemodule/README.md)
-* [Exercise on coupling free and porous medium flow (SFB PA A)](./exercise-coupling-ff-pm/README.md)
-* [Exercise on discrete fracture modelling (SFB PA B)](./exercise-fractures/README.md)
-* [Exercise on biomineralization (SFB PA C)](./exercise-biomineralization/README.md)
+The DuMu<sup>x</sup> course comprises the following exercieses. Each exercise folder contains a detailed description of the tasks
+(best viewed online by following the link) and the header files to work on.
+
+### [:open_file_folder: Exercise on the basics](./exercise-basic/README.md)
+
+Based on a scenario, where gas is injected into an aquifer, you will learn how to
+
+* compile and run an executable
+* see the difference of a two phase set-up without component transport compared to a two phase two component set-up
+* set up a new executable
+* set up a non-isothermal test problem based on the isothermal test problem
+* set boundary conditions
+
+### [:open_file_folder: Exercise on the main file](./exercise-mainfile/README.md)
+
+In this exercise, you learn how to
+
+* find your way in the main file
+* solve a stationary, linear system
+* solve an instationary, linear system
+* solve an instationary, nonlinear system
+* apply analytic differentiation
+
+### [:open_file_folder: Exercise on runtime parameters](./exercise-runtimeparams/README.md)
+
+This exercise covers the following topics: You learn how to
+
+* use different input files with one executable
+* set variables to collect runtime parameters
+* use and change default values for runtime parameters
+
+### [:open_file_folder: Exercise on grids](./exercise-grids/README.md)
+
+This exercise guides you through the following tasks:
+
+* apply a global grid refinement
+* change the grid type
+* apply grid zoning and grading
+* read in structured and unstructured grids from external files
+
+### [:open_file_folder: Exercise on properties](./exercise-properties/README.md)
+
+In this exercise, you learn how to adjust the properties in order to use a customized local residual
+
+### [:open_file_folder: Exercise on fluid systems](./exercise-fluidsystem/README.md)
+
+This exercise covers the handling of phases and components in DuMu<sup>x</sup>. You learn
+
+* how to implement and use a new, customized component
+* how to implement a new fluidsystem
+* change the wettability of hte porous medium
+
+### [:open_file_folder: Exercise on how to create a new Dune module](./exercise-dunemodule/README.md)
+
+You learn how to
+
+* create a new dune module linked to the dumux module
+* create a new GitLab project
+
+### [:open_file_folder: Exercise on coupling free and porous medium flow](./exercise-coupling-ff-pm/README.md)
+
+This exercise is related to the [SFB1313 Project Area A](https://www.sfb1313.uni-stuttgart.de/research-areas/)
+
+You learn how to
+
+* use a coupled problem set-up
+* change coupling conditions between the two domains, porous medium flow and free flow
+* change the shape of the interface between the two domains
+* change the model in the porous medium domain
+* change the model in the free flow domain
+
+### [:open_file_folder: Exercise on discrete fracture modelling](./exercise-fractures/README.md)
+
+This exercise is related to the [SFB1313 Project Area B](https://www.sfb1313.uni-stuttgart.de/research-areas/)
+
+You learn how to
+
+* use a problem containing embedded, discrete fractures
+* change the properties of the fractures
+* use domain markers to set internal boundary conditions
+
+### [:open_file_folder: Exercise on biomineralization](./exercise-biomineralization/README.md)
+
+This exercise is related to the [SFB1313 Project Area C](https://www.sfb1313.uni-stuttgart.de/research-areas/)
+
+You learn how to
+
+* include a chemical reaction in the problem set-up
+* apply the mineralization model, i.e. apply balance equations to possibly changing solid phases
+* compare different simulation results using a programmable filter in paraview
+