Bought one today, very cheap, works OK (as seen in NETTO)

1)  If target m/c is VCR/DVD etc, make sure a tape/disk etc, is loaded.
2)  Look up code for your TV/VCR etc.
3)  Press & hold SET key.
4)  Select TV1 (e.g. if a TV is target m/c); led comes on, release both keys. You now have 10 secs to input code.
5)  Input 3-digit code, - led goes out. Done.
Repeat, using TV2 etc for second target m/c.
If code is incorrect, led flashes twice and stays on. Try inputting correct code this time!

Hope this helps.
JW