include botan 2 in compilation

i try include some botan header in compilation process

#include <botan/rng.h>#include <botan/auto_rng.h>#include <botan/cipher_mode.h>#include <botan/hex.h>#include <iostream>int main(int argc, char** argv){        return 0;}

I found that i need to compile with following command in order to build successfully

g++ app.cpp -I/usr/local/include/botan-2

i saw some folks execute

g++ app.cpp -lbotan-2

i tried it out but i get a error

'app.cpp:1:10: fatal error: botan/rng.h: No such file or directory #include <botan/rng.h>

Am i missing anything ?