Explanation
The Surround activity with mock option is used to create a mock activity that wraps around the original activity in the workflow. The mock activity can have different properties and actions than the original activity, depending on the testing scenario. In this case, the MessageBox activity can be surrounded with a mock activity that has the LogMessage action. This will replace the functionality of the MessageBox with a LogMessage during mock testing, which can be useful for logging the test results without interrupting the workflow execution. (UiPath Studio documentation1) References:
1: Configuring Activity Project Settings - UiPath Studio.

Explanation
The Anchor Base activity is used to automate interaction with an application when the element selector is not reliable and the element's position on the screen changes. The Anchor Base activity consists of two parts: an anchor and an action. The anchor is a UI element that has a reliable selector and a fixed position relative to the target element. The action is the activity that performs the desired operation on the target element. The Anchor Base activity uses the anchor to locate the target element based on its relative position (left, right, top, bottom) and then executes the action on it. This way, the automation can handle dynamic and complex UI elements that have unreliable selectors or change their position on the screen. References: Anchor Base and Example for Anchor Base Activity from UiPath documentation and forum.

Explanation
Credential stores in UiPath Orchestrator are used to securely store sensitive information like Robot credentials and Credential Assets, which are essential for executing automated processes that require login details or other secure data. Orchestrator supports multiple credential stores at the tenant level and provides built-in support for secure stores such as CyberArk and Azure Key Vault. It also allows for the development of plugins for other secure stores if needed. (Orchestrator - Credential Stores - UiPath Academy) References:
Orchestrator - Credential Stores - UiPath Documentation Portal
Credential Stores - UiPath Orchestrator

Explanation
To configure the Filter Data Table Wizard to keep all invoices with a Total value that is over 10 000 USD, you should choose the following options from the drop-down lists:
Column: Total Operation: > Value: 10000
The reason for choosing these options is to filter the data table based on the condition that the Total column value is greater than 10000. This will keep only the rows that satisfy this condition and remove the rest. You can learn more about the Filter Data Table activity and how to use it from the following sources:
Four Ways to Filter Data Tables in UiPath Studio | UiPath
How to Filter Data Table - Help - UiPath Community Forum
Filter Data table with specific column - UiPath Community Forum

Explanation
The Automation Developer installation package is a standalone installer that allows you to install UiPath Studio, Assistant, and Robot on your computer. This package is suitable for developers who want to create and test automation projects in UiPath Studio. (UiPath Studio - Installation Options - UiPath Academy) References:
Studio - Installation Options - UiPath Documentation Portal
[UiPath Studio - Installation Options - UiPath Academy]
[UiPath Studio - Installation Guide - UiPath Academy]