To set up LWC Local Development, install the server, enable and authorize a Dev Hub org, and create a scratch org.
The Local Development Server is a Salesforce CLI plug-in that configures and runs a Lightning Web Components-enabled server on your computer. You can develop Lightning web components and see live changes without publishing the components to an org.
Basic Setup: https://trailhead.salesforce.com/content/learn/projects/quick-start-lightning-web-components
Run this command from a command-line interface.
sfdx plugins:install @salesforce/lwc-dev-server
SFDX: Start LWC Local Development Server
SFDX: Open Local Development Home
or SFDX: Preview Component Locally
SFDX: Stop LWC Local Development Server