Hi Sindhu,
You can create custom tables by clicking Enter Data Button under the Home tab.

Click on * to add new Columns/rows.

Now enter the table name and Double click on the columns to add columns.
You can also add data by Double-clicking on the data cells.
The Column that is created in already existing tables can be added in the new table by merging or creating a relationship between them.
Hop this helps you.
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