You can read that in the manual which came to your version of PBP.
Here then a smal example with no comment. Try to find the comment in the manual.
Code:
		
			@ DEVICE PIC16F877A,XT_OSC
			@ DEVICE PIC16F877A,BOD_OFF
			@ DEVICE PIC16F877A,LVP_OFF
			@ DEVICE PIC16F877A,CPD_OFF
			@ DEVICE PIC16F877A,PROTECT_OFF
		

		
		
			DEFINE	ADC_BITS		8
			DEFINE	ADC_CLOCK		3
			DEFINE	ADC_SAMPLEUS	50
			DEFINE	OSC 4
			
			ADCON1	=	%00000010	

			TRISA		= %11111111
			TRISB		= %00000000   
			TRISC		= %10000001

			LEDPIN		VAR	PORTB.0

			VALUE0		VAR	BYTE

			CLEAR
			

START:			ADCIN 0,VALUE0

			IF VALUE0 > 127 THEN
				LEDPIN = 1
			ELSE
				LEDPIN = 0
			ENDIF

			GOTO START
			END