There can be various reasons why your trading strategy isn't placing orders:
The trading strategy you're using doesn't frequently trigger a buy or sell. Check how often your strategy provides buy and sell signals using the strategy backtester.
You've selected too many technical indicators that need to give a buy or sell signal simultaneously before a buy or sell order is placed. Consider selecting fewer technical indicators that need to give a buy or sell signal before a buy or sell order is placed on your crypto exchange.
You've selected too few cryptocurrencies that your trading bot is allowed to buy. Check this in "Currencies and amounts" in the Base config.
In the trading bot output on the Dashboard or Advanced Dashboard, there may be trading bot errors that prevent the placement of orders. Review the errors and adjust settings as needed in the Base config.