If you are trying to find a fic off tiktok and they didn’t provide a link, I highly recommend using this, it is so much easier than trying to find it by the name.
Type in the user you want to finds name. For example: the god of fanfiction themself tbhyourelame, author of heat waves.
You can see how the suggested name pops up, there is a limit to how many search results show up under that but that’s never been an issue for me. You just need to keep typing the name in.
You don’t need to click the specific name cause it will just show all the close searches.
ao3 will show a list of these user boxes under the search, click on the one you want and you end up on their profile page
You can click on their works in the column on the left or just scroll through their recent works in the main bit, but that only shows the most recent 5(?) before you have to click show more.
This is where having an account comes in handy. Users can set fics to only show to registered ao3 members for whatever reason. So if you are not logged in, you can’t read heat waves/helium on ao3.
Since I am now logged in it shows 7 instead of 3 works, and you can see helium right there. Ao3 member only fics are indicated by the blue lock next to the title + author