Building my credit from zero.?

I work at a furniture store that does in house financing and I want to use that to establish credit from zero. I was told I can purchase something for about $200.00 and put half down and make payments on that to start establishing credit. Is this true? I'll be paying only on $100.00 per month so will that even matter or will that be a good way to establish credit. I was also told creditors look at how long your payments are so if they're taking that long to pay off then will that help me at all. Is it worth it?