The way to promote is to apply for a role when it opens in a team which you like and apply like any regular person but there will be a huge advantage to applying as a graduate due to already having experience in that said team. The openings in teams are sometimes rare but opportunities still come up every now and then.
Yes, they do offer opportunities to move up the company, takes hard work and a keen interest on the role that is being offered.
There are opportunities but we are not all fairly given the chance to apply for these as some managers have already decided on who they want and are just doing the hiring interest messages as due diligence. This brings up the question of why advertise the role if you have already made up your mind and are not going to decide on the right fit by assessing all applicants.
Not many of the rotations that can be done seem to actually have roles available for graduates. Its seems like the company is taking on too many graduates compared to how many teams actually need extra hands.