Open table from Data Model > Tables > table_name in Studio.
Select Columns tab. Now can see the fields in table. Some of these fields (like Created by, Created,…) are system fields and already there.
To add your fields (new fields) click on New button or double click on last row.
After double click on “Insert a new row”, should give a label to field.
Then needs to set the field type. Double click on it, then by click on type browser button, you can select field type from a list of types.
Then click on Update button.
To set more options on field, click on field label.
In Dictionary entry window you can set if field is mandatory or read only.
If needs to remove the field from table, you can click on Delete column button, but better way is to unchecked the Active item.
To set international labels for table, go to Labels tab. As you see en is default language for labels (in my system), to add more languages click on New button.
Now enter the new label and set language, then click on Submit button.
As you see, two labels for different languages are set.