I have used Ubuntu for over a year and decided to try Debian - I'm fairly familiar with the basics by now. I installed Debian 9.0.0 from a *large* [ISO file][1] (~3.5GB) using a bootable USB. My WiFi hardware needs [additional tweaking][2], and hence unless I do that first, I can't install anything using `apt-get`. 

While trying to get my WiFi working, I realized that I have very few packages/programs installed by default after the fresh install. For instance, for fixing the WiFi, I needed to use `make` - which didn't work because I had no `build-essential` installed. So, without internet, I tried to install `build-essential` using the ISO file mounted (and `/etc/apt/sources.list` updated appropriately). However, as expected I was met with a large number of Unmet dependancies, and at one point I noted that **I did not have `gcc` installed.**
Similarly, I have found `linux-headers` not installed. 

**Question**: Does Debian follow a do-it-yourself approach (like I heard Arch Linux does)? Or have I gone wrong somewhere (in the installation, or afterwards)?

I don't work in the CS field and I can't afford to install all basic packages from start - I use my machine for work. Any help would be appreciated. Thank you.

EDIT: I found [this post][3] relevant. However I don't even have `aptitude` installed on the system, by default. 

  [1]: https://cdimage.debian.org/debian-cd/current/amd64/iso-dvd/
  [2]: https://askubuntu.com/a/729660/586050
  [3]: https://unix.stackexchange.com/questions/90523/what-packages-are-installed-by-default-in-debian-is-there-a-term-for-that-set