Follow the
LINK to signup for your Writesonic account. You can get started for Free with their limited Free Tier or Sign up for their flexible monthly/annual subscriptions based on your word count needs.
Once you have your account created, access your API Key from the API Dashboard found under your account details in the top right of the screen while you are logged into your Writesonic account.
Then put your API Key into the plugin and get started using this excitingly powerful generative AI.