First cambelt I ever did the instructions said something like 'try not to disturb the settings by rotating the engine'
Of course, sods law dictated that I had to rotate the engine slightly for something or other & I kinda panicked a little.
Then I thought "how the hell do they set these things up when brand new?".
Of course, all the important cogs have indicator marks on them which should line up perfectly with indicators on the belt.
Take your time to ensure these marks all align perfectly & you should have no trouble.