nice to hear from you again!
Here you can find very detailled information about the further proceedings (German language):
I will give a brief summary in English here:
In general you can apply for a "unbefristete Niederlassungserlaubnis" (unlimited settlement permit) at Ausländerbehörde after 5 years. But there is quite a lot of criteria that you need to fulfil:
First of all BAMF will check if the circumstances in your home country got better and if you can go back. Furthermore they will check if you are a threat to the Federal Republic of Germany or the safety of its people (including your criminal record - if there is one).
Apart from that you will need to provide evidence that you can earn a living (Jobcenter/Sozialamt must pay less than 50% of your total income), that you have a health insurance, that you have enough housing space for you and your relatives, and basic knowledge about German society and culture. Plus: your level of German has to be A2 or higher.
If you want to apply after 3 years already, then two things change. First: your German has to be C1 or higher. Second: Jobcenter/Sozialamt must pay less than 25% of your total income.
I will link our awesome lawyers @Marcel and @Steven so that they can share their knowledge as well.
Feel free to ask further questions if necessary :)