Where to make Logical Design ?

Reference to Physical Design, I am confuse that where we make this design. ER model we make on but what about logical and specially physical design. Where we make these design ?

Logical design deals with gathering business requirements and converting those requirements into a model. After this information is gathered, diagrams are produced including entity relationship diagrams (ERD), business process diagrams, and process flow diagrams (DFD).
After logical database design, the Physical Database Design starts. The first step is to create an initial physical data model by transforming the logical data model into a physical implementation based on an understanding of the DBMS to be used for deployment. To successfully create a physical database design you will need to have a good working knowledge of the features of the DBMS including:

1. In-depth knowledge of the database objects supported by the DBMS and the physical structures and files required to support those objects. 
2. Details regarding the manner in which the DBMS supports indexing, referential integrity, constraints, data types, and other features that augment the functionality of database objects. 
3. Detailed knowledge of new and obsolete features for particular versions or releases of the DBMS to be used. 
4. Knowledge of the DBMS configuration parameters that are in place. 
5. Data definition language (DDL) skills to translate the physical design into actual database objects. 

The transformation consists of the following:

1. Transforming entities into tables 
2. Transforming attributes into columns 
3. Transforming domains into data types and constraints