Making a simple AC/DC power supply

I thought the 7805 made 5v,

It does but you can only feed it with 35V maximum so you need to cut this down with a zenner diode first. Either that or a regulator with a higher input voltage.

the caps for the 7805 should be in the uF range?

They are on the output of the diodes he says:-

Capacitor 470 - 1000uF

Note you need a 50 or above working voltage on these capacitors.

7805 blocked with two 100nF caps,

That means a 0.1uF cap on the input and output of the 7805, although I would go for something bigger, say 4.7uF on the output side.

Some switching supplies while requiring a mains input could work at 30V AC.