The 4032 is a computer system with a monitor, keyboard, internal power-supply and a motherboard. On the motherboard you will find a MOS 6502 processor, RAM / ROM memory, MOS 6545 video-chip, MOS 6520 PIA and a MOS 6522 VIA.
The 4000 series is the successor of the PET-2001 with a bigger screen, type-writer keyboard and more ROM and RAM memory.
The 40 in the model number stands for 40 columns of text on the screen and the 32 stands for 32 kbyte RAM memory.