Use this to specify how block symbols are generated. It is available from Insert Block Instance
Locating this option
Available from: Insert menu > Block Symbol > option
How to define a generated block symbol
Firstly, you need to specify the styles to use. The pins style is used for all the pins on the symbol. You can specify an existing style, or define the parameters of a new style. The outline style is used for body rectangle of the symbol and for the pin legs.
Three length parameters are used to define the size of the block rectangle, and the length of the port pin legs.