Define Bridge

Bridges the external adapter to plugin node
You can add external adapters to a Plugin node by creating a bridge in the Node Operators Interface. Each bridge must have a unique name and a URL for the external adapter. If a job has a Bridge Task, the node searches for a bridge by name and uses that bridge as your external adapter. Bridge names are case insensitive.
To create a bridge on the node, go to the Create Bridge tab in the Node Operators Interface. Specify a name for the bridge, the URL for your external adapter, and optionally specify the minimum contract payment and number of confirmations for the bridge.
Bridge Name - Must be unique to your plugin node and it is user defined. For instance, if your external-adapter brings your temperature value. Name it as "Temperature" so you can easily refer back what does the bridge does
Bridge URL - it should be the URL where the external-adapter is running. Mostly try to set this up in your server where plugin node is running.
Minimum Contract Payment - is a fee paid in PLI for the Plugin node making a call to the external adapter via the bridge. This fee is in addition to the fee specified at the global node level for processing job requests.
Confirmation - can leave it to 0
For example -
Note : if external-adapter is running in same server as your plugin node. Keeping it as localhost should be sufficient like above.