What can I do if my company is not paying my salary?

Sir, I was working in an office on post of desktop engineer I was not hoping any great improvement in that office that's why I left the job but after leaving the job I didn't get my left payment it was more than 10k I have talked much about the topic to the manager but he did nothing except using bad words for me so I am thinking of giving him legal notice about it I am not that financially strong so I want to figure out it myself but I have not much information about it so can you please kindly help me regarding this matter I saw your videos on YouTube that's why I came here I want information like how to give a legal notice do I really need to get a Lawyer for giving legal notice to a company? Please help.