AS4QGIS can be downloaded via this Google Drive link. The folder 'AS4QGIS' contains 4 subfolders. To ensure that the algorithm pipeline works, at least one of the provided models and the folder 'styles' are required.
models | contains the '.model3' algorithm pipelines. Synthesis and Psyche.
styles | Contains the (optional) style files.
In the QGIS processing toolbox click on 'models' and 'add model to processing toolbox...'. Navigate to the downloaded model of AS4QGIS Synthesis and/or Psyche and add it.
In the Processing Toolbox, Right-click the model and choose 'Edit Rendering Styles for Outputs...'.
A Pop-up will appear. Click the button '(...)'.
Navigate to your previously saved '.qml'-style files.
Once the file path has been set, the style folder should not be moved. Otherwise, the file path must be set again.
The styles-folder is downloadable via the google drive-link or via github.
for polygons.shp choose AS4QGIS_polygonstyle.qml
for polylines.shp choose AS4QGIS_polylinestyle.qml
for vertices.shp choose AS4QGIS_pointstyles.qml
for pointdata.shp also choose AS4QGIS_pointstyles.qml
Your output files are now styled.