Welcome to the community @socialstijn!
Great that n8n looks interesting for you and that you want to create an integration.
Information about creating an integration for n8n you can find under the following pages:
What is also helpful is to check existing integrations. You can find them here:
You can simply look for one that works similarly to the one you want to create. On its page, you will then find a link directly to the source code of the node.