Recommended way is to create symlinks in the OpenMQTTGateway repo dir pointing to each individual env config file located in this repo.
Optionally you can create secret_env.ini (ignored by the Git) taking secret_env.ini.example as an example and populating it with relevant values. This will completely disable ESP WifiManager and configure OpenMQTTGateway using variables provided in the secret_env.ini
Example:
cd /path/to/the/OpenMQTTGateway
ln -sf /path/to/the/omg-envs/omg_grower_env.ini .
ln -sf /path/to/the/omg-envs/omg_d1mini_rf_env.ini .
ln -sf /path/to/the/omg-envs/secret_env.ini .