If you want to collect payments from your clients, first of all, you have to open and confirm your Mistertango account following this instruction:
After that login to your Mistertango account, then go settings section „Payment Collection Settings“, enable payment collection service, choose a module, enter shop website address (URL) and Callback address (URL). When you will do that, the system will provide you with the secret key and username for the next steps.
You can find all the e-shop modules and helpers on : modules & helpers
If you will have more questions, please write to firstname.lastname@example.org