Need Help to setup uplink and downlink using SX1280 GW and Nucleo STM32L073RZ

I am a student trying to learn about LoRa and also I’m new to this portal. I have a SX1280 transceiver and a Nucleo STM32L073RZ with me. With the help of some academics and friends I have already started to work on how to send packets form Node to Gateway(Uplink) using the [lorabasicsmodem] and [gateway_2g4_hal] from GitHub. However, I am still not able to figure out the communication the other way around i.e. from Gateway to Nodes (downlink). I may be doing something wrong here which I have no idea of. I’ve spent weeks trying to figure out a way. My question here is, is there a way to have both, the uplink and downlink to work between the GW and node and is there any extra documentation which can guide me through it. Up to now I have used the [User Guide to the LoRa® 2.4GHz 3 Channels Single SF Reference Design] to understand the utilities and the connections. However, I am stuck now and need some guidance to proceed forward to have atleast some basic communication working between node and GW, especially for downlink. It would really help me learn LoRa in detail if someone could give me pointers to start working on and offer me guidance on how to use these two devices specifically. Thank You in advance.

Resources used:

Gateway -

Node Modifications for Working Uplink -