Extract Acquisition parameters

acqus_df = px.extract_params(root_directory=main_directory)

Extract Free Induction Decays (FID)

fids_df = px.extract_fids(root_directory=main_directory, acqus_df=acqus_df)

You can plot raw FID using px.plot:

px.plot(x=fids_df.columns, y=fids_df.iloc[spectrIndex].apply(np.real), title='Free induction decay')