There are two ways to combine your tables. The question is, do you need to work with each data set individually or together?
During the import data source process, you can combine all data sources you select into one dataset, and therefore into one table. However, if you need to work with each as a separate table before combining in Xcalar, you can import them as multiple datasets, and then use the union operator to combine them, when appropriate.
See the following for details on how to multi-select and import as separate datasets: https://discourse.xcalar.com/t/import-each-document-in-a-directory-as-separate-data-source/459
The steps are virtually identical to import as one dataset.
As far as merging the tables after some modeling operations, you'll use the union operator. Here's how:
Select Union... from the column menu from one of the tables.
Select whether you want to merge all rows, or deduplicate.
Select all of the tables you want to union.
Enter a name for the combined table.
Select the columns you want to union.
Click UNION ALL.