Solidworks top-down assembly design [Creating a Part in an Assembly]

Two types of assembly designs are used in Solidworks software.
1. Bottom-up assembly design
2. Top-down assembly design
In bottom up assembly design, parts are made individually in Solidworks part mode then we make new assembly using assembly mates.
While using Solidworks top-down assembly approach, we can do followings things.
-Create part within an assembly
-Edit features of a parts in assembly mode
-Makeing new sub-assembly wihtin an assembly