Hi!
Sample command you can execute from the root repo directory (just replace IP and PORT with starting peer - either DNS seeder or any zcash node):
cargo run --release --features crawler --bin crawler -- --seed-addrs "IP:PORT" --rpc-addr 127.0.0.1:54321
And then just grab the results from running crawler from the other console:
curl --data-binary '{"jsonrpc": "2.0", "id":0, "method": "getmetrics", "params": [] }' -H 'content-type: application/json' http://127.0.0.1:54321/ > latest.json
It will dump results in the JSON file. Please give the crawler some time to work 
The progress will be printed on the console (you will see the messages about generating summary - that summary can be then taken using curl).
Please also look at the:
https://github.com/runziggurat/zcash/blob/main/src/tools/crawler/README.md
to get some more information about the crawler.
Regards!