Right click on the table and choose select top 1000 rows.  This will give you just the top 1000 rows. You will see the sql  which generated this and can remove 'TOP 1000' and click execute to see the whole table or change the SQL to pick up specific records, by adding a 'Where' clause.

Alternatively  click on 'Views' (Below Tables) and right click on New View. This gives you a window which enables you to create queries. Drag the table you want into this and select the fields required.

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