If you’re converting the Biped-originated-FBX to Biped rig, you don’t need to map the skeleton. Select any bone on the rig and open mapping window to check whether it mapped.

    While if you’re converting an FBX previously not originated Biped, you need to map it manually if there is no template for this type of character.

    • (Primary) Mapping body
    • Mapping fingers
    • Mapping toes
    • Mapping accessories
    • Mapping body secondary bones.

    :::success Tip
    How to mapping in 3ds Max, see more on How to Mapping :::