ERPnext M-Pesa integration guide?

hello i have been trying to integrate M-Pesa in ERPnext but unable to do it and it says please check your credentials, i referred to the documentation but could not figure it out without going live. i just want to test it out without going live. is there a step by step guide for it?

i have the short code, Passkey, security credential etc. but i dont know what i am missing please help.
It would be great if someone can guide me a little bit in it step by step.