@it-shiki your english is not as bad as you think
To mount entity:
C02PacketUseEntity(Entity, C02PacketUseEntity.Action.INTERACT)
https://scriptapi.liquidbounce.net/net/minecraft/network/play/client/C02PacketUseEntity.html
To move entity:
C0CPacketInput
https://scriptapi.liquidbounce.net/net/minecraft/network/play/client/C0CPacketInput.html
To jump on entity:
C0BPacketEntityAction(Entity, C0BPacketEntityAction.Action.RIDING_JUMP)
https://scriptapi.liquidbounce.net/net/minecraft/network/play/client/C0BPacketEntityAction.html