Thanks @Necrotos for pointing to the MLC document, I think for now this tutorial would be a good start to get familiar with MS tuning. Another useful introductory tutorial might be the TVMCon recording for MetaSchedule.
Other than these, another example of tuning for onnx could be found here: https://github.com/apache/tvm/blob/748882aae7be1435f042e22b0fc67cb236705b6c/python/tvm/meta_schedule/testing/tune_onnx.py