2003 CTS 3.2 timing help

Hello I need a little help timing this engine. First off I got the car and they said the timing jumped. Well I got it all took a part down to the timing belt. All 4 cams line up with the marks on the back of the cover. But the crank don't line up on the bottom mark. To me it looks 90 degrees out of time. What I want to know is can I lock the cams down with the lock out tools then loosen the belt alittle then turn the crank to the bottom mark and it should be good to go? I have all the info on how to time it but what I don't get is it says to time the crank at 60 degrees and not right on the bottom mark. So if that's the case my motors only 30 out not 90. I hope someone understands what I'm saying and can help me out.

First of all how did this get out of time if the belt and tensioners are ok? There are special tools to hold the cams. A factory shop manual should be referred to here.

First of all how did this get out of time if the belt and tensioners are ok? There are special tools to hold the cams. A factory shop manual should be referred to here.
I got the car like that. They said the serp belt broke and made it jump time. I have the tools that lock the cams out and the one for the crank. All I need to know is if I can lock the cam TDC then just put the crank on the bottom mark and it should be good to go