For this, you can do trainings on this on their academy site and get a certificate on same. When you go to academy and select “Test Suite” as a product, it will show up different trainings/courses(as shown below) you can undertake for same.
Along with that, you can take up below indepth course on RPA testing as well.
Doing all of these courses should be good to enhance your skills as a RPA tester 
Hope this info helps.
Regards
Sonali
sharazkm32
ashokkarale
marquezd
RGTaffy
SorenB
cprima
KB_Fleet
Nithinkrishna
V_M_P_Bharath
Nisha_K21