Bidibobidibu you have to improve your forum's page rank by improving its SEO.
Search Engine Optimalization (SEO) is a process during which you focus on improving your page's visibility in search results. The way Google (and most big search engines) work is that they take into consideration various factors of your website, such as the quality of the content, number of visitors, popularity, and SEO tags. SEO tags are a collection of predefined rules that you can define in order to get a better rank (for example, you can set a description for your forum in order to get a higher page rank). The higher your page rank, the higher you appear in search results. Normally, these tags are set by Flarum or its extensions automatically, but sometimes your manual intervention is required.
Setting up all of this and getting a good page rank can be a long process, especially if you are completely new to this topic. I've made some very basic introduction to the world of SEO for you, but I'd strongly recommend you to Google about SEO and learn, since I don't consider myself to know much about this topic either.
And as for Flarum, there are numerous discussions regarding this topic. You can browse through some of them - Flarum's SEO might not be perfect at the moment, but it's getting there. The developers are now focusing their radars on improving it in the next couple of updates, so I expect Flarum forums to be ranked higher more easily in the near future.
What you can do now is enable the SEO extension. It is an amazing extension that will guide you through the process of setting up everything that's necessary for a better SEO of your Flarum forum. Other than this, I also recommend you to submit your forum to Google's search console, which helps you a lot.
