Open conditions section (1) and select Query condition type (2):

You can use Standard or Advanced config mode to create condition.

Standard Query config mode allows user to create condition using only process data source object fields, while selecting Advanced Query config mode adds Object picklist where user is to choose from the list of available objects (3):

• Click "Add Condition" button
• Fill blank fields with values
• Add more conditions

Values can be of different types: 

• Value - some static value
• Field - values of the the fields of the Source object
• Formula - compare with Merge fields of Context objects using formulas.

Provide condition logic expression if necessary (4):

Condition logic is build based on list of conditions user created.

To use conditions in Logic expression one needs to operate conditions Index values. So {1} will represent Opportunity.Closed = TRUE condition, {2} will represent Opportunity.Fiscal_Quarter = 2 condition, etc.

Following operators can be used when creating logic based on list of indexed conditions:

• OR   evaluates if at least one of multiple values or expressions is true.
• AND   evaluates if two values or expressions are both true.
• NOT(expression that you want evaluated) - Returns FALSE for TRUE and TRUE for FALSE.

( )   specifies that the expressions within the open parenthesis and close parenthesis are evaluated first. All other expressions are evaluated using standard operator precedence.

{BR}  operator is used to create WHERE part of Condition logic. Everything that goes after {BR} works the way clauses do after WHERE statement in Salesforce Object Query Language. Use SOQL SELECT Syntax after {BR} operator.