Its not that difficult if you are the guy calling the shorts, for example Qatar spent $200b on the World Cup iirc, how much of that do you think was siphoned to private pockets through manipulation of tendering processes?
Up until 2021I used to work for the government in procurement of state projects and I knew the chain of people who were bribed each time a contractor was paid. A contractor leaving up to 20% of his invoice value in the hands of civil servants wasn't unheard of. Then there would be that one contractor that everyone knew belonged to the boss, he would leave his cut only to the boss andthe figure would be 10%. These projects were small, maybe one million there, five million here but the side payments were made or the contractor knew he wouldnt get paid.
Now expand that scenario to an oil rich country with less than 500k people to look after and billions coming in daily. He is the guy who made the decision whether to invest in this bank or that fund and he didn't even need to steal from his state, well literally, as anyone in need of capital knew he had to pay him off inorder to secure investment for the growth of his firm or the execution of their project. The kickbacks he would have had access to would have Blatter and Platini wishing they felt Qatari.