how do you "bleed the radiator " after you replace a bad hose?

Basically, you "burp" your radiator/coolant reservoir cap to let the air come out when the level starts getting high. Start and run your vehicle - get it to operating temperature. An air pocket in your system will make it seem like you will overheat - temperature gauge will typically go up beyond normal, and the level will get very high. Leave the cap on - secure but loose. When the level gets very high, protect your hand and arm but release the cap and allow the air bubble out. Repeat until the coolant level stabilizes.