A TLSA record lives at _port._protocol.host, for example _25._tcp.mail.example.com, with three fields: certificate usage (0 PKIX-TA, 1 PKIX-EE, 2 DANE-TA, 3 DANE-EE), selector (0 full certificate, 1 SubjectPublicKeyInfo) and matching type (0 exact, 1 SHA-256, 2 SHA-512), followed by the data. 3 1 1 (pin the server's own public key by SHA-256) is the most common choice because it survives certificate renewals with the same key.
Browsers never adopted DANE, but SMTP did: RFC 7672 uses it to make opportunistic STARTTLS between mail servers authenticated and resistant to downgrade, and Postfix, Exim and large providers such as Microsoft Exchange Online support outbound DANE validation. MTA-STS is the WebPKI-based alternative.
Key rollovers need a published record for the next key before the switch; the TLSA record generator computes records from a certificate or key.