If you created a sub, by default not a single person get notified about it: it can only be seen in the communities list of your instance. But don't worry it's pretty easy to change it

How to get people see your community

1. Write good description of what it is about, what is going to be posted, what's to be expected
2. Craft instance agnostic link to it. Replace "!sub-name@instance" for yours in this link (see the footnote for Lemmy 0.18+)[^1] [Search to federate this sub to your instance](/search/q/!sub-name@instance/type/All/sort/TopAll/listing_type/All/community_id/0/creator_id/0/page/1). It will direct people to search for your community on their own instance.
3. Post it to meta/main community of your instance: for example !meta@sopuli.xyz
4. Also post it to lemmyverse community-promo sub
5. Start posting!

That's it, by reposting it just twice you dramatically increase discoverability of your community. Of course you may find additional community-promo subs but posting in at least these basic two is a good start

Good luck!

[^1]: Lemmy 0.18.0.
[This link will fetch CommunityName to your instance](/search?q=!communityname%40instance&type=Communities&listingType=All&page=1&sort=TopAll)
Change communityname with community name, and instance with instance link (without https://)