You should read the code to understand how the example work, it contains various comments where your attention is needed or where choice needs to be made.
To run the example:
# We assume you are in ./examples/basic
go run . mainnet.eth.streamingfast.io:443 https://github.com/streamingfast/substreams-eth-block-meta/releases/download/v0.5.1/substreams-eth-block-meta-v0.5.1.spkg db_out