It looks like Merx is missing. Please check site/plugins/merx.
You can install Merx manually by downloading Merx and put the files into site/plugins/merx.
Alternatively, you can clone the Git repository as described in the installation instructions. With git submodule init/update Kirby and Merx are downloaded automatically into the correct directories.
I believe there is a route somewhere missing. It might be good to have a look at the starterkit at https://starterkit.merx.wagnerwagner.de/ to get a better feeling how this would work.