What is available balance in Coinbase?

Could you please elaborate on the concept of "available balance" in Coinbase? I'm curious to understand how it differs from the total balance and what factors determine its amount. Additionally, how does the available balance impact my ability to trade or withdraw cryptocurrencies from the platform? Is there a specific time frame associated with the availability of funds in my Coinbase account? Finally, are there any fees or limitations associated with accessing my available balance? Thank you for clarifying these points.