The process_select_files_data finds data (recording) files that are already imported in the Brainstorm database. To add a raw data to the database as "link to raw", use the process process_import_data_raw.
If you have already the "link to raw" in your database, you can use any of following process to import the recordings. There are examples of their use in many of the provided tutorial scripts:
process_import_data_eventTo import epochs around events from raw file
(example intutorial_introduction.m)process_import_data_epochTo import epochs from epoched raw file
(examplein tutorial_ctf.m)process_import_data_timeTo import an specific segment from row files
(examplein tutorial_epilepsy.m)
Edit: Added info on processes process_import_data_*