I've read the Nakamoto's paper "Bitcoin: a peer-to-peer electronic cash system". In paragraph Simplified Payment Verification he said that is possible to verify payments without running a full network node.
I don't understand how, having a Markle's Tree Root hash, verify payment. In fact, in order to check payment, I need to combine and hash all node of right or left branch, not just the root.
Moreover, how can choose which Root hash needs to get without see in all nodes?