Wetland_1d.vtu and KineticReactant2.vtu are 1D meshes with uniform element sizes. They can be generated, e.g., with the generateStructuredMesh, something like:
generateStructuredMesh -o mesh.vtu -e line --lx 3 --nx 50
KineticReactant2_2d.vtu is an unstructured mesh. It can be generated, e.g., with Gmsh. The Gmsh output can be converted to files suitable for OGS, e.g., with msh2vtu from our emerging ogstools Python package.
The documentation of our tools is being improved, currently.
Soon, there will be a tutorial covering many aspects. You might already want to take a look at the current status: Merge Request !4457, tutorial preview (note: the second link might break, soon, because it’s only a preview.)