Clicking Add Table will ask for the name of the table and then create a table with the name, and create the corresponding primary key.
Clicking Add Parent will ask for the name of the parent table and then create a parent table with the name, create a primary key, and then create a foreign key on the current table pointing to the parent. It will also create an index for the foreign key.
Clicking Add Child will ask for the name of the child table, then create the child table with the name, create a primary key, and then create a foreign key on the child table pointing to the current table. It will also create an index for the foreign key.
Clicking Add Many To Many will ask for the names of the two parent tables and the intermediate table. Both parent tables and the intermediate table will be created with the linked foreign keys. It will also create indexes for the foreign keys. It is possible to link to existing tables with an intermediate table by simply specifying the existing tables as parents.