Welcome to the forums, @Markco92.
As you’re new to SEO, the best place to start is Google’s “Search Engine Optimization Starter Guide”.
I also suggest you have a look around the forums, as we have many threads on the subject. We have a couple of active discussions here:
How can i improve my off page SEO
I invite you to join in those discussions, if you have further questions, rather than duplicating things here in a new thread.