Yarn start not starting up

i am trying to follow https://www.elastic.co/guide/en/kibana/7.9/development-getting-started.html . But when i do yarn kbn bootstrap I get the below error. Instead of cloning I downloaded the branch.

[4/5] Linking dependencies...
warning " > @elastic/eui@29.0.0" has incorrect peer dependency "typescript@^3.7.2".
warning " > @testing-library/react-hooks@3.4.1" has unmet peer dependency "react-test-renderer@>=16.9.0".
warning "workspace-aggregator-bca0f563-b93f-46bd-9f2b-84e4ad131dae > x-pack > @elastic/apm-rum-react@1.2.4" has incorrect peer dependency "react-router-dom@^4.0.0".
warning "workspace-aggregator-bca0f563-b93f-46bd-9f2b-84e4ad131dae > x-pack > react-shortcuts@2.0.1" has incorrect peer dependency "react@^0.14.8 || ^15".
warning "workspace-aggregator-bca0f563-b93f-46bd-9f2b-84e4ad131dae > x-pack > react-shortcuts@2.0.1" has incorrect peer dependency "react-dom@^0.14.8 || ^15".
[5/5] Building fresh packages...

 succ yarn.lock analysis completed without any issues
ERROR [bootstrap] failed:
ERROR Error: Command failed with exit code 128: git log -n 1 --pretty=format:%H -- C:\Users\Anjana\Downloads\kibana7.9\kibana\kibana-master
      fatal: your current branch 'master' does not have any commits yet
          at makeError (C:\Users\Anjana\Downloads\kibana7.9\kibana\kibana-master\packages\kbn-pm\dist\index.js:26713:11)
          at handlePromise (C:\Users\Anjana\Downloads\kibana7.9\kibana\kibana-master\packages\kbn-pm\dist\index.js:25648:26)
          at process._tickCallback (internal/process/next_tick.js:68:7)
error Command failed with exit code 1.```

Can you double check your node version and do a yarn kbn clean && yarn kbn bootstrap?

Thanks

I had to do git commit --allow-empty -m "first commit"

did it work ?

yeah it went ahead ..