Hi, welcome to Pokebase. About your question about where the flag button is, the reason you don't see it is because you don't have enough point to be able to flag posts, as you need 40 points to do so.
https://pokemondb.net/pokebase/meta/10194/how-do-i-get-extra-privileges-e-g-voting-and-wall-posting
Check out that link to see the required amount of points to be able to do stuff like flagging posts, voting on posts, etc.
I'd also recommend checking out this link to learn about how points work:
https://pokemondb.net/pokebase/meta/202/what-are-points-and-how-do-they-work
Anyways, have fun here. :)
