vSTARS is the primary controlling tool you will use. It has your radar screen, flight plan editing abilities, and communication capabilities. This is the software you will use to connect to VATSIM. This lesson will cover how to set it up prior to your first session on sweatbox. It will also cover ZLA specific notes on using this software.
A detailed vSTARS setup video for your first sweatbox session (after passing the clearance delivery exam) can be found at https://laartcc.org/page/vstarsvideo