First of all: Welcome!
Don't be upset, it is just a phone!
Secondly: Do not think about it as complicated, because it is different... And do not expect the device to change for you. It is linux, it is different and you better try to pick up as much and as often as possible.

Now: There are two ways to get your fonts into the system.
The graphical way: Install filebox file manager from the extras repository. It shows you the real file-system of the device while the in-build Hildon File Manager cripples your file system to internal card and external card. Both these cards are formatted vfat or fat32. These cards are mounted to /home/user/MyDocs and /media/mmc1.
With filebox you are able to browse to /home/user, where you might create the folder .fonts/ and put your fonts into it.

The Terminal way: Assuming you have downloaded and extracted your font to the N900 card. Open X-Terminal application, Adapt the path please if your download location differs. Or ask again