Stripe is a reputable and simple to use payment gateway. You don't need to deal with any code to use Stripe with Chec.
Go to Settings > Payment Gateways and click on Enable Stripe.
Simply add your Public and Private Stripe Keys and you are good to go!
To use your Stripe sandbox API keys, you'll need to use your Chec testing API keys. These can be found here.
If you haven't got a Stripe account already, register a new account with Stripe, It takes about 10 minutes to get setup.