First read the overall project contributing guidelines. These are all included in the qiskit documentation:
https://qiskit.org/documentation/contributing_to_qiskit.html
In addition to the general guidelines there are specific details for contributing to ibmq-schemas, these are documented below.
Once you've made a change, it is important to verify that your change does not break any existing tests and that any new tests that you've added also run successfully. Before you open a new pull request for your change, you'll want to run the test suite locally.
To run tests first make sure all the dev requirements are installed in your Python environment with:
pip install -r requirements-dev.txt
Then you can run the tests with
python -m unittest -s ./tests -t ./tests -v
from the repo root.