Given Sequential Function Chart (SFC) needs these three basic elements... B:initial step, C: transition, and D:next step
Steps define a process, and transitions define the condition(s) for moving to the next process.
The step with the double-line frame is the initial step. Execution of an SFC chart begins at the initial step.
Within the "Step" and "Transition" areas contains actual functional code. (IE: Ladder Logic, Structured Text or even Function Blocks). So basically Sequential Function Chart (SFC) is just an organizational overlay that contains the Ladder Logic/Diagram (LD) and/or Structured Text (ST). Just like Function Block Diagram (FBD) contained actual code (LD or ST) to work. So both SFC and FBD are just an organizational overlay, you still have to write the program in LD or ST. So a much simpler way would be to just use a PLC instead of a PAC, and use subroutines to organize your sequence of events.
Note: If a program is huge and/or complex like a PAC controlling an entire plant, multiple systems and machines interconnected, a flow chart with navigational functionality (SFC) with understanding inter-connectivity and navigation. Its all about using the right tool for the right job when programming, maximizing reliability and reducing downtime. the same reason you don't see computers controlling bicycles.
Below Elevator SFC subroutine will get you started and a general since of how to organize, but of course if you want complete system designed for you with needed ladder logic, etc. you would have to pay someone like IEEE $33 for the full document (Or google other students work, both would be cheating if this is a student project.)
You can look in LogixPro PLC simulator examples for elevator ladder logic example, then just divide up within each appropriate step in a SFC program. (same with many structured text elevator programs.) Google is your friend there.