Which question do you want to trace?
Where could you start with a real question?
If a receiving address changes, that does not mean your old outputs moved. Start with the keys lesson to separate authority from a label, then use address types to identify the kind of destination a new output will use.
How should you connect these guides?
Begin by separating authority from encoding. A private key participates in signing, a public key supports verification, and an address describes a destination for an output. Those objects are related, but each answers a different question. If an explanation treats them as interchangeable, use the first lessons here to reconstruct the missing steps.
The address-type lesson identifies the output construction. The encoding lesson then examines how that destination becomes copyable text with a checksum. Read them together when an interface rejects a destination: the reason may involve network, version, program length or checksum variant. No recognised prefix proves that a destination belongs to the person you intended.
Multisig adds a threshold condition rather than a larger single-user password. Follow it after keys and Script if you want to distinguish key possession from complete spending authority. The custody guide connects these mechanisms to the practical question of who holds the required secrets and recovery information.
For a worked reading exercise, imagine an output that needs signatures from several possible keys. First identify the condition, then the committed script, then its encoded destination. Reverse that route when studying the later spend. You should be able to explain which public information a node checks and which secret information remains with the signers. The sources under each lesson define the encoding and validation details behind that route.
When you finish, you should be able to trace a receiving destination back to the kind of condition it represents. That does not reveal a hidden secret or verify a recipient; it gives you the right objects to inspect.
Where do the mechanisms come from?
Sources: Public-key cryptography reference; Standard transaction destinations.