visit http://127.0.0.1:8000/subgraphs/name/daostack/
This should give you a graphiql interface.
If it says "not found", you may need to run npm run setup-env
curl --include \
--no-buffer \
--header "Connection: Upgrade" \
--header "Upgrade: websocket" \
--header "Host: 127.0.0.1:8001" \
--header "Origin: http://127.0.0.1:8001/subgraphs/name/daostack/" \
--header "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \
--header "Sec-WebSocket-Version: 13" \
http://127.0.0.1:8001/subgraphs/name/daostack/
Your resonse should look like: