Update side quests index and titles

Author: vdauwera

docs/side_quests/index.md

@@ -6,22 +6,18 @@ hide:
 
 # Side Quests
 
-[TODO] This is a collection of standalone training modules that go deeper into specific topics. You can go through them in any order.
+This is a collection of standalone training mini-courses that go deeper into specific topics. You can go through them in any order.
 
-Let's get started!
+Let's get started! Click on the "Open in GitHub Codespaces" button below to launch the training environment (preferably in a separate tab), then read on while it loads.
 
 [![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/nextflow-io/training?quickstart=1&ref=master)
 
-## Learning objectives
+## Prerequisites
 
-The learning objectives are specific to each section. [TODO]
+The specific prerequisites of each mini-courses vary and are documented in the corresponding pages.
+Nevertheless, they all assume some minimal familiarity with the following:
 
-## Audience & prerequisites
+- Experience with the command line
+- Foundational Nextflow concepts and tooling covered in the [Hello Nextflow](../../hello_nextflow/) beginner training course.
 
-[TODO]
-
-**Prerequisites**
-
-- A GitHub account
-- Experience with command line
-  [TODO]
+For technical requirements and environment setup, see the [Environment Setup](../../envsetup/) mini-course.

docs/side_quests/nf-test.md

@@ -1,4 +1,4 @@
-# Side Quest: nf-test
+# Testing with nf-test
 
 Being able to systematically test that every part of your workflow is doing what it's supposed to do is critical for reproducibility and long-term maintenance, and can be a huge help during the development process.
 

docs/side_quests/workflows_of_workflows.md

@@ -1,4 +1,4 @@
-# Side Quest: Workflows of Workflows
+# Workflows of Workflows
 
 One of the most powerful features of Nextflow is its ability to compose complex pipelines from smaller, reusable workflow modules. This modular approach makes pipelines easier to develop, test, and maintain.