Without Rust

The verifier page runs in the browser. Open it from a checkout:
Then use its three examples: The second verifier needs no Rust either. It checks everything except the Halo 2 proofs:

With Rust

The first build takes about ten minutes.

Make a receipt

From a viewing key and a seed phrase, on separate machines if you like:
create makes the proofs with no spending key. sign shows everything the receipt reveals and asks before signing. The seed phrase is typed or piped in, never put on the command line.

Verify

Compose

A batch of payments proves they were signed by one key:
The other relationships have their own commands; start from the composability overview.