This guide is specifically prepared for investors trading cryptocurrencies like Bitcoin, Ethereum, and others. The core focus is teaching how to use "trading volume" to judge market trends and assist trading. Here's a simple summary:

1. Understand the basics: What exactly is trading volume?
Trading volume refers to the total amount of cryptocurrency traded within a certain period. Its main role is to assess market activity and capital participation. The key is to look at the "price-volume relationship": when prices rise, trading volume should also increase, indicating strong support and a reliable trend; if prices go up but volume shrinks (few traders involved), the rally is likely unsustainable and may reverse.

A small additional note: different exchanges may have varying rules for calculating volume, which can sometimes be inflated; on-chain data (actual transfer records on the blockchain) can exclude fake trades and provide more reliable reference.

2. How to interpret volume across different timeframes?
- Intraday short-term (same day): Focus on 1-minute and 5-minute volume. For example, when breaking above the previous day's high or other key levels, insufficient volume may indicate a "false breakout"; if the price hits a new high but volume doesn't follow, a pullback is likely.
- Mid-term (weeks to months): Watch 5-day and 20-day average volume. If short-term average volume remains higher than long-term, the uptrend is stable; on weekly charts, a breakout from a consolidation zone with increased volume may signal the start of a mid-term rally.
- Long-term (major trend): Combine with large on-chain fund movements. For instance, at the bottom, if volume steadily increases but price remains stable, it could indicate "smart money" (professional investors) quietly accumulating, potentially leading to a big move later.

3. How to use volume in extreme market conditions (sharp rise/fall, sideways)?
- During sharp rises: If prices keep climbing but volume gradually decreases, it suggests a top is near; a breakout with historically large volume indicates a solid move with room to run; if volume suddenly spikes but price stalls, it might be a trap set by big players to lure retail investors.
- During sharp declines: Use the "pyramid averaging" method (adding small amounts as the price falls), but stop adding after a drop of over 10%. Prioritize reducing positions to manage risk; also monitor large on-chain fund movements to avoid bottom-fishing in the middle of a decline.
- During prolonged sideways trading: Volume drops below 30% of the yearly average, indicating market sentiment is low and bulls and bears are stalemated; a subsequent increase in volume often signals a potential breakout (up or down).

4. Differences in volume analysis between mainstream coins and altcoins
- Mainstream coins (Bitcoin, Ethereum): More reliable, clear volume-price patterns (rising with volume, falling with shrinking volume), high liquidity, large trades won't significantly impact price; can also incorporate derivatives volume (futures, options) to confirm trends.
- Altcoins: Higher risk, small funds can cause sharp price swings. Sudden volume spikes often indicate hype or manipulation; the trend may lack sustainability and sometimes show "price rising but volume falling" anomalies. Always cross-check with large on-chain transfers to verify signals.

5. How to apply these techniques in actual trading?
- Master basic indicators: For example, OBV (to judge capital flow), VWAP (institutional average cost), avoiding reliance on price alone, which can lead to misjudgments.
- Multi-dimensional validation: When breaking key levels, volume should be at least 1.5 times the daily average to be credible; combine data from different timeframes and exchanges to avoid false signals from a single platform.
- Practice + strict risk control: Use demo trading to test strategies (e.g., "buy on volume breakout, sell on volume decline"), and in real trading, set strict stop-loss and take-profit orders; never rely solely on volume signals for decision-making.
- Adjust strategies flexibly: Bull and bear markets require different volume interpretations; altcoins are suitable for short-term trading, quick entries and exits, while mainstream coins can be part of long-term plans. Don't stick to one method all the time.

Summary: Trading volume is a key tool for judging market authenticity and understanding capital movements. The key is to apply it flexibly across different timeframes, coins, and market scenarios, combined with other data and risk management rules, to effectively improve trading success rates.