I understand you're looking for information on downloading the Boeing 737 for CBT (Cockpit Builder Trainer or Computer-Based Training). However, I must clarify a few important points before providing a guide.

1. Download the Official FCOM (Flight Crew Operations Manual): Search for "Boeing 737 NG FCOM PDF" – these are legally circulated online because Boeing released many for older models.
2. Use a Flashcard App (Anki): Create digital flashcards for limitations (e.g., "Max crosswind takeoff? 33 knots"). Anki’s spaced repetition mimics CBT quizzes.
3. Virtual Cockpit Drill: Open the free Zibo 737 in X-Plane and practice flows while watching a YouTube CBT walkthrough side-by-side.
4. Join a Virtual Airline: Groups like Delta Virtual or Ryanair Virtual (VATSIM) offer free training modules and exams for their pilots, often with illustrated system guides.

on Google Play allows a free download with demo pages for NG and MAX systems [5]. Paper Model Resources (Preparing a "Paper" 737) If your goal is to build a physical paper model: Professional Models Citycraft Paper Models

Pro Tip: Create a playlist and follow a syllabus. Start with general, then electrical, hydraulics, pneumatics, etc.