I just launched a new certification prep section on my site, starting with the Microsoft Power BI Data Analyst cert (PL-300). This came out of pure frustration with the current state of exam prep materials.
Most of the good study content is locked behind subscriptions. Udemy courses, practice exam sites, bootcamp platforms - they all want recurring payments for content that honestly should be more accessible. I get that content creation takes work, but when you're already paying for the exam itself, stacking another hundred dollars in study materials on top feels predatory.
So I built my own. Free. Open. Using real data from projects I actually work with.
What I built
The PL-300 section has three main components.
Practice Questions - Over 100 questions across all four exam domains (Prepare Data, Model Data, Visualize & Analyze, Deploy & Maintain). Not just multiple choice. I included true/false, multiple select, matching, fill-in-blank, drag-and-drop - all the question types Microsoft actually uses on the exam. Each question has explanations, difficulty ratings, and tags so you can filter by topic.
Hands-On Case Study - This is the part I am most proud of. It is a complete guided project where you build a full Power BI dashboard from scratch using real gym performance data. Not some sanitized corporate dataset. Actual lifting data from my own tracking system. You download three CSV files, import them into Power BI, and work through 25 implementation steps covering the entire workflow: data cleaning, star schema modeling, DAX measures, visualizations, publishing, security, refresh schedules. Everything.
Real Data - The case study uses my actual gym data. Thousands of sets, exercises mapped to muscle groups, body part dimensions. You can download it all as a ZIP file and use it for whatever you want. Build your own dashboards, practice SQL, experiment with DAX. I do not care. The data is there.
Why this approach works
Here is what I learned from working through PL-300 prep myself: reading slides and watching videos only gets you so far. You need hands-on practice with messy, real-world scenarios. You need to build the wrong thing first, see why it breaks, then fix it. That is how the concepts stick.
The case study forces you to make decisions. Should you use Import or DirectQuery? Single or bi-directional relationships? How do you handle exercises that do not map cleanly to a single muscle group? These are the questions that show up on the exam and in real projects. Clicking through slide decks does not prepare you for them.
The plan moving forward
PL-300 is just the start. I want to build this into a full repository of certification study tools across different domains. Next up: DP-600 (Fabric Analytics Engineer) and AZ-305 (Azure Solutions Architect). The pattern is repeatable: structured questions, hands-on projects, real data.
I am also considering adding progress tracking and spaced repetition for the practice questions. Right now it is just static content, but tracking which questions you have answered and surfacing the ones you struggle with would make the prep more efficient. That feels like a natural next step.
Why make this free
Two reasons.
First, paywalls suck. I hate seeing good educational content locked away when the barrier to entry is already high enough (exams are expensive, studying takes time, certifications expire). If I can lower that barrier even slightly, I will.
Second, building this makes me better at the material. Writing good questions forces me to understand edge cases. Building realistic projects forces me to think through implementation details. Teaching is learning, and putting this content out publicly holds me accountable to quality.
Try it yourself
The certification section is live now at /certifications. Download the gym data, work through the case study, test yourself with the practice questions. If you find issues or have suggestions for other certifications to add, reach out. I want this to be useful.
Much love, Dillon
