Trouble about ardupilot to Px4

We are using cube orange ,when we use ARDUPilot our radio turns PWM when we change it ARDU to PX4 radio turns Sbus( we are using Sbus).When we turned to we cant see altitude on card. What is the problem we need help !!! (radiolink t8FB receiver is r8EF).I cant change PWM to SBUS on Mission Planner and QGround.