First and foremost: thanks for sharing your experience in becoming a trader!
Coming back to art of learning, initially, I would suggest that you learn to read two to three signals and see if the signals are aligning with the chart. I recommend you to use candlestick for chart since it has numerous ways to tell you how the future market rating could be by the past market chart patterns.
I disagree in this point. Backtesting and forward demo/paper testing isn't about "testing knowledge" (yeah, for beginners this might be surely also a reason). It's about getting enough numbers on a strategy/signal/whatever from which a trader can make a decision if it fits his expectancy enough to risk real money. How will you know, if a strategy gives you a positive expectancy, what the win ratio, what the average and resulting RR, … will be or if it'll lose you money, if you never put it up to test before you're putting money on the table.
Utilizing back and forward testing is what a professional trader does. If you cannot trade without feeling the excitement, it'll bite you in the long run.
To put it in other words: given two traders start using the exact same strategy – which works in stocks very well – in crypto. One is going live right away, the other is demo'ing for 150 trades to gain number. After three months both find out, that this strategy has a negative expectancy in crypto due to higher volatility. Difference: the live-guy lost time and real money before he did find out, the demo-guy did only lose time.