How do hashes package transactions into blocks?

"A mining computer reduces transaction information to an encrypted alphanumeric string called a hash, using bitcoin’s SHA-256 algorithm to produce a fixed-length result. Even a tiny change in the underlying information produces a completely different hash, while the original information can be checked against the hash for verification. Miners combine the hashes of successive transactions into a continuing hierarchy, allowing many transactions to be grouped into a single block whose contents can later be verified through the unbroken chain."