Multi-part components are components that contain multiple functional units of the same type. For example, component 74HC00 contains four two-input NAND ports. It is possible to represent this component with a single symbol but in many cases it is more convenient to be able to draw the four NAND gates separately so that you can place each gate independently of the others at any point of the schematic.
To construct the complete symbol of the 74HC00 component, you can use the symbol of a two-input NAND gate and specify the number of parts that make up the component. Perform the following operations:
Click the Open library button. The dialog box for selecting the library file opens.
In the dialog box, select the "Logic" symbol library and click the Open button. The library opens.
Scroll through the tree structure and select the symbol "NAND_2INP" then click on the button Add section. A new section is added.
In the section line, click on the Parts box and set 4 parts.
In the section line, click on the Index box and choose Prefix. If you choose Prefix, the pin names are prefixed with the index of the part.
In the Name box, specify a name for the symbol.
Click on OK.