Belt gets adjusted automatically when you turn crank with a belt on and tension roller loose. When you turn it on 180-360 degrees a tension spring puts proper tension on a belt. After that you should tight a bold on tension roller and you all set.
When I did timing belt on my civic (I'd think that Accord goes same way) I started the engine without timing belt cover and belt was playing a lot at idle RPM on both streams. It was looking better at 1.5k RPM and higher. After I saw that I was under impression that belt wasn't tight enough. I put more tension on roller manually and by sound I could tell that it was wrong. So I set adjustment the way it was first time, put a cover, and just forgot about it for another 100K.