Attract the first subscribers from your contacts. In the settings, you can add other social networks and sign up people who are your friends. They'll get a notification and can decide whether or not to subscribe back, so it's quite delicate compared to, for example, sending out subscription requests in private messages.
Or ask for help at https://viplikes.net/ You can promote your brand or your services on multiple social networks at the same time, or at least post a link to your business page on other accounts. You can also repost regularly, or even publish posts automatically on several social networks at once.
You can attract the attention of potential subscribers by commenting on posts on related blogs, profiles of other bloggers, or thematic communities. In this way you can show your expertise, for example, by answering someone's question or wit. You can express your point of view, disagree or even argue, the main thing is not to get personal, and do not insult anyone. Also, be active by subscribing and liking other profiles.