Fulfilling your Jewishness means learning about your obligations as a Jew, called mitzvot, commandments, so you can fulfill them. Which means you need to learn Torah. I collected here resources for a beginner wanting to do so. There are plenty of online resources as well (start here at chabad.org for instance).
Most important is to find a guide in learning to live as a Jew, ideally a trained rabbi who has helped others in your circumstances. For this you should turn to one of your local Orthodox Jewish communities, hoping there are one or more where you live. That rabbi can help design the right growth plan for you, which will likely include participating in community events, Shabbatot, holidays, etc.
Feel free to ask more questions here if we can be of help.