The serial input basics tutorial will show how to read and parse a packet of data. It shows how to listen for serial input, take the data in a byte at a time and parse the data when a whole packet is received. Also how to arrange the packets for reliable reception.
Packets of data can contain data of several different data types (byte, int, string, ... ) arranged in a comma (or whatever) delimited packet with terminating marker and, optional, start marker.