How to register, fire and handle a component and application event?

We register an event by by using the following code:

<aura:registerEvent name=”sampleComponentEvent” type=”c:compEvent”/>

We fire event as shown below:
var compEvent = cmp.getEvent(“sampleComponentEvent”);

compEvent.fire();

Handle component event as below :

<aura:handler name=”sampleComponentEvent” event=”ns:eventName”

    action=”{!c.handleComponentEvent}” phase=”capture” />

Handle Application event as below:
<aura:handler event=”c:appEvent” action=”{!c.handleApplicationEvent}”/>