After I turn on the bot does it start trading immediately?

It depends on your settings. If you don’t have any signals or filters it will enter the market within a minute. In case you do have one or many filters or a signal bot will enter the market only when all conditions are met.

No filters - high deal frequency but more risk, as no market analysis.

One or several filters - more reliable trades as special programs are monitoring the market and allow bot to trade only when the market goes in your favor, but usually less deal frequency.