I've already read the doc that you've provided, but what I've asked is not in this document (in short, if you don't specify/limit the uplink bandwidth, and if from the provider you've bought only 10Mb, what will be the reference bandwidth used for High Normal and Low clases?
Meraki doc says:
Each traffic rule supersedes each rule below it and the rules below it must strictly adhere to their fractional bandwidth limits. For instance, if there is a high traffic shaping rule but no low traffic shaping rules configured then the high priority traffic would have access to 5/7 of the available bandwidth on the uplink and normal traffic would have 2/7s. Additionally, if there are no high priority traffic shaping rules then normal priority traffic gets 6/7 of the bandwidth and low priority gets 1/7 of the uplink's bandwidth.