There is a freebsd port of apt in /usr/ports/sysutils/apt/
You must install the ports collection to use this; there is a pbi for the ports collection.
Once the port is available, there are several installation methods; the basic manual method is to open a root terminal session, cd to the port you want to install, and enter 'make install'.
Installing software from packages and ports is covered in the freebsd handbook at
Note however that freebsd (and pcbsd) linux emulation is based on fedora, not debian, so some linux apps that you install via apt-get may not work as expected.
You may find that the debian apps you are looking for are available as native freebsd apps in the ports collection. You can look up ported applications at