Inside your Kometia Admin, go to the Settings -> Add Method section.
Inside your Conekta Admin you can find the API keys you need for your Kometia shop.
Return to your Kometia Admin (Settings → Payment Methods). Locate the Conekta module and click on Add Method.
Paste your private and public keys in the corresponding fields, and click Accept.
Finally, inside the Payments Method section, review that the module there is active.