Can anyone explain the GS Career Ladder Program?

That means you start as a GS-11. After a year assuming you have successful performance your boss may promote you to 12. A year after that 13. I use the word may, because it isn't guaranteed, but I have never seen someone held up either. Congrats on the position!

Not sure what agency you were hired into, but basically you will promote as you meet certain career milestones, be they time of service, career achievement or performance standards. These should be spelled out in your "contract", and are not negotiable once you've successfully completed each milestone. Review the written job offer and make sure that this is covered in detail.

Welcome to bean counting. A little more clarity here. A career ladder position offers the opportunity to be promoted on a noncompetitive basis. Several conditions need to be met. First, it can't be a supervisory position. Second is a time in grade aspect. For that level, it's more likely 2 years each. Third, you must be able to perform at the higher level. That's not an automatic. There should be some pedigree things you'll have to do in the credentialing arena. And finally, the thing out of your control, the work at the higher level must exist. We had a couple of career ladder financial types that got capped early because our finance authority wasn't increased as planned (to AAA Accounting Activity). The higher level work never materialized, hence the applicable grading factors didn't increase. They moved on fairly quickly to another organization.

Typically you have a career ladder position for series in which the job specifics are best met by a lot of OJT and other developmental activities. The systems you work in are unique. This type of position is established because there's a problem in grabbing qualified workforce. If the GS-13 work existed and qualified candidates were available, you'd just do a Merit Systems fill. There's a morale issue with them too. Other employees will be jealous of your cleared pathway and not knowing the ins/outs of the HR system, will feel they're second class citizens. Don't rub their noses in it. And finally, finance on the Fed side is serious business. Don't get too "creative".