That code might work with an other 1602 display, i don't know.
That is why i didn't say it wouldn't, but told you it is much more complicated than using the LiquidCrystal library.
These blocks you see are an indication that there is no correct initialisation.
That can happen if you power the unit, but aren't able to communicate with it.
The link i found didn't show a picture of the connector (i decided not to download an extra language pack, so might have missed something).
But the 4002 (if i remember correctly) brother of this display has a similar double row of solderpads.
They are numbered like this, facing the viewing side of the display, the solderpads to the left of that display.
Left row from bottom to top is even, right row from bottom to top is odd.
16 15
14 13
12 11
10 9
8 7
6 5
4 3
2 1
Normally on connections like these, pin 1 is indicated (the rest can be derived from that).
It will have some kind of marking next to it, or it may be the only square solderpad (the other ones are round).
You probably want to tie pins 5 and 6 to GND, at least for a simple test sketch.
And you might want to use a resistor to reduce current on 15 or 16 (doesn't matter which of these) , if this module doesn't do current limiting itself.
Ofcourse you need to tell the sketch what Arduino pin connects to what display pin too.
Did you do that ?