If you are sure you did not lose the top dead center position you could gently rotate the crankshaft in the normal direction of running a couple of times with the belt installed as it is. The error you have might be due to the belt not yet having settled in, so its tension is not yet really distributed all along its length.

By pulleys I assume you mean the idler and tensioner. If you didn't remove or rotate the cam sprockets or rotate the crankshaft without the belt you should not have problems. My bet is the belt will settle in the correct position. If it settles so you are a full tooth off on one or both sprockets you will then see how to adjust it.

I put mine on crankshaft first, then intake sprocket then exhaust then idler and tensioner. I had to hold the belt under very firm tension while routing it from crankshaft to intake sprocket, to avoid leaving an extra tooth in that space.