You can use the Assembly Member dialog box to specify which member of the alternate assembly you want when placing a subassembly into an assembly or when replacing a subassembly in an assembly.
Member
Specifies the alternate assembly member you want to use for the assembly you are placing or the assembly you are replacing. You can also define a new alternate assembly member by selecting the Dynamic Configuration option to display the Dynamic Configuration dialog box.
Browse
Displays the Replacement Part dialog box so you can select a replacement part or assembly. This option is available only when replacing an alternate assembly.
Search
Displays the Search dialog box so you can define search criteria for a replacement part or assembly. This option is available only when replacing an alternate assembly.