I realised what happened. I've downloaded Pd from Ubuntu software center and it installed everything where it's supposed to go. What now confuses me a bit is that in the software center you can find the following: puredata, puredata-core and puredata-gui. If you go for puredata-core it advices you to also download puredata-gui. If you go for gui, it advices you to download puredata-core, or even puredata...
Well, I've downloaded puredata and it's working (although it crashes if I try to open the 'Test audio and midi' patch), and it's located at /usr/bin/ and the rest are located at /usr/lib/puredata (btw, it's version 0..43.0-4, not the current...), but still no icon, still this warning at the Pd window: WARNING: Font family 'Courier' not found, using default (DejaVu Sans Mono) and still no makefile (I guess the software center took care of it).
Well, I'm sticking to the makefile cause I'm going through Lyon's 'Designing audio objects for max and pd' and he's making use of Pd's makefile when compiling an object...so I guess I'll need it, right?