Studying a language is a challenge, but it has many great rewards. To begin the process, choose a language at Ethnologue. Then do a web search for materials, language courses at universities, and study groups.
If there are not many options for your language, do not despair. Begin a self-study and join or form a group on social media. Once you start, stay committed to the process. The attention and interest you bring to the language will help others as well, and eventually bring more attention to the language.