Explanation:
Provided versions 1.0.0.0.0 and 2.0.0.0.0 are both less than 6 months, the version restored by the customer will be saved as version 3.0.0.0.0 which means there will now be 3 versions.
Reference:
https://learn.microsoft.com/en-us/power-apps/maker/canvas-apps/restore-an-app

Explanation:
Box 1: Trigger Phrase
A trigger phrase is a phrase that a customer enters in the chat window to start a conversation with the bot. Once the conversation is started, the conversation follows the path you define. You can specify more than one trigger phrase for a topic.

Box 2: Variable
Variables let you save responses from your customers in a conversation with your bot so that you can reuse them later in the conversation.
Box 3: Entity
An entity can be viewed as an information unit that represents a certain type of a real-world subject, like a phone number, zip code, city, or even a person's name.
Reference:
https://docs.microsoft.com/en-us/power-virtual-agents/authoring-create-edit-topics
https://docs.microsoft.com/en-us/power-virtual-agents/authoring-variables
https://docs.microsoft.com/en-us/power-virtual-agents/advanced-entities-slot-filling

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/working-with-data-sources

Explanation:
https://docs.microsoft.com/en-us/power-apps/maker/data-platform/data-platform-intro#terminology-updates