Squizza, time spent now just learning about C strings and string.h functions will save you a lot of time and headaches in future.
Here is a start point to build/experiment from:
// link to AVR LibC string.h library
char mywords[ 32 ];
Serial.begin( 9600 );
strcpy( mywords, "Hello World" );
Serial.println( mywords );
substring = strstr( mywords, "World" );
if ( substring )
Serial.println( substring );
Serial.println( "World not found." );
I would point you to the Arduino tutorials->examples page but some Idiot loaded a bunch of C++ String examples there -- maybe that's why so many new users think that C++ String objects are the way to go. Sure, you -can- use them if you don't do much but as a practice they are Bad for such small environments.