E32 433D 1w two way receive/transmit

Hi all, thanks for this library. I am trying to establish bidirectional communication(both sending and receiving structures) between said model. My goal is to transmit from node 1 to node 2 as fast as possible, and receive from node 2 every 1000 ms etc. I successfully talk these modules one way already.But having hard times when it comes to two way communication. Using stm32 hardware serial on both ends. Any idea highly appreciated.