This is Max from the Shopify Team.
The easiest way to do this would be to create some price-based manual shipping rates.
This means heading to Settings > Shipping > scroll to the Zones and rates section > click Edit next to the relevant shipping zone. You're able to set the limit for these new rates based on a minimum order price!
Be sure to Save any changes.
Let us know if you need any more clarification. Feel free to share a screenshot of your current rates so we can take a look.