Re: few questions about trading

1: what is the different between spot trading and futures trading.

Your first question, in my opinion the most complete and easy answer for you to understand, you can see here: Commodity Spot Prices vs. Futures Prices: What's the Difference?

2: between Stop Limit or Stop Loss and
OCO or order cancel order which is the safest for trading.

3: At what level is overleveraging.

4: between spot trading and futures trading which is highly risk and highly reward that uses leverages.

for question 3 I don't understand the question and for 4 the answers are already on pages 1&2.