!! Beginner Queries!!

Dear Crypto Fam!

I had a few queries, some of which I could not get satisfiable responses to despite "scalping" the internet as well as searching a bit around in this Community.

1. When does Binance calculate fees based on the spread? When we buy directly from Binance?
2. Can we add a trailing stop loss in Binance?
3. Is there a limit on the number of trades within a 24-hour period?
4. Do you get charged on unfulfilled buy / sell orders?

All are in reference to the spot market.

Also, I am new to this type of thing, so please feel free to add something you think I should know.

Thanks In Advance, Fellow Crypto Fam!