How much debt is too much debt?

[James Quinn]

So I've been getting into real estate investing recently and i just finished the bigger pockets ultimate beginners guide and learned a lot. But one thing that was not mentioned, and i cant find a lot of people talking about it, is debt in your properties. Lets say you have 20 properties all worth $100,000 and you only put $10,000 down on each property. While these properties could be cash flowing $200-$400 each, a month, you only have about $200,000 in equity over all of your properties, and $1,800,000 in debt. This seems like a lot and seems very dangerous. Could a newbie get some advice? Thanks :)