Setup Assistant in Marketing Cloud provides a guided setup for configuring new accounts and covers various topics to streamline the process, including:
A). Enabling Mobile Connect: This section guides admins through setting up Mobile Connect, which allows them to send SMS and MMS messages to mobile devices.
C). Configuring Journey Builder: This part of the Setup Assistant helps set up Journey Builder, guiding users on how to create and manage customer journeys effectively.
Reference: Salesforce Help - Setup Assistant

For a non-technical marketing user to manage a campaign sending renewal reminders:
Data Filter: Use Data Filters to segment customers based on the expiration date included in the data file. This enables targeting customers 15 days and 7 days before subscription expiration.
Template-based Emails: Implement template-based emails to allow the marketing user to easily update and manage email content without needing technical skills or administrative rights.
Automation Studio: Utilize Automation Studio to schedule and automate the sending of these emails based on the specified criteria, streamlining campaign management.
Reference: Salesforce Marketing Cloud Automation Studio