CCS/MSP-EXP432P401R: PWM_open with customed pins?

Part Number:MSP-EXP432P401R

Tool/software: Code Composer Studio

Hi, I am new to Ti Micro-controller. I have just read the example project pwmled2_MSP_EXP432P401R_tirtos_ccs from simplelink_msp432p4_sdk_2_40_00_10 where the program inits the PWM pin with

pwm1 = PWM_open(Board_PWM0, &params);

Then I wondering how I can open another PWM on pins like TA2.1 etc. but when I browse through the definition of Board_PWM0 in Board.h, I only found these:

#define Board_PWM0                  MSP_EXP432P401R_PWM_TA1_1
#define Board_PWM1                  MSP_EXP432P401R_PWM_TA1_2

I am wondering why there is only 2 PWM output pin is defined and how I can use the ti/drivers/PWM.h on the other pins. Thanks.