We have just created a demo for UrbanAccess that shows you an entire workflow in a jupyter notebook that can be accessed here. Before running the notebook make sure you are running the latest version of urbanaccess as changes have been made as of today, use git pull from the cloned directory or re-clone the library. If you go through the demo you should have a better understanding of the API and the workflow.
Once you complete the demo (restart the notebook to clear memory), you can substitute the code specific to the demo in the notebook for your own code and try your process again. Let us know if after you have done this you have any issues.
In direct response to your messages though:
From the messages and code you provided it looks like the parameters you are passing to ua_network_from_bbox are incorrect. The function docstrings and documentation should provide the necessary information to run the function correctly. For example, you should only specify the four lat and long parameters or the bbox parameter, not both. If using the bbox it needs to be a tuple eg: (14.1957,52.2312,12.5807,52.8019) and network_type must be either
drive. For the headway function to work you need to have loaded GTFS data with the gtfsfeed_to_df function. To use the gtfsfeed_to_df function you must specify the location of your GTFS feeds on disk in the gtfsfeed_path parameter or use the global variable for this.
If you run through the demo though this should clear up the confusion.