Using multiple IF statements in calculated fields

[steveo250k]

I'm trying to create a calculated field in an ad hoc using multiple IF statements. The thing is I'm not sure how to connect the statements. Below are the statements that i'm trying to use.  

IF("Origin Appointment Time" == null, 'NO APPOINTMENT') 

IF(ElapsedHours("Origin Appointment Time", "Origin Arrival Date") < 2,  '< 2 Hours')

 

if(ElapsedHours("Origin Appointment Time", "Origin Arrival Date") > 2,  '> 2 Hours')

 

if(ElapsedHours("Origin Appointment Time", "Origin Arrival Date") > .5,  'ON TIME')

[sfriedman]

You can next IF functions. Here is a sample with the Foodmart sample data.