For more details see the Stripe Payment extension page.
Simply integrate your Magento store with a flexible and fast-growing payment gateway - Stripe and provide your customers with a user-friendly and safe payment experience.
To activate the payment method click Enable - 'Yes'.
Specify the frontend title of the Stripe payment in the 'Title' field.
API Publishable Key - get the key from your Stripe account
API Secret Key - and this kee you can also find in your Stripe account
Merchant Country - here you need to name a merchant's country that you set in the Stripe Account.
Sort Order - here you can set the order in which the payment methods will be displayed on the checkout page.
For more information, please, visit Stripe documentation (it's really nice indeed).