Head over to https://platform.openai.com/

Register, or log in with your account.

Create your API Key

Copy your generated API Secret key.

In Site Settings→ Apps & Plugins enter your Open AI API secret key

Setting up the price

Please run a test with your images.

The official price list is here

https://openai.com/pricing

In general should cost 0.04$ per avatar style generated.

In Site Settings → Apps & Plugins → Open Ai → Price for generated you can enter the price