Unlike spot trading, in futures trading you can sell a coin you do not own. This process is called shorting. Shorting is simply betting against the coin. In longing, we bet that the coin will go up, in shorting, we bet that it will go down.
Apart from the fact that we click sell instead of buy, there is no difference in the technicalities involved in selling/shorting.
NOTE:- • Closing a sell/short trade manually is the same as in buying/long.
When already in a trade, you can adjust your leverage and also change your stop loss and take profit still in the positions tab anytime by clicking on
them.
Hope this will help.
And OP you have to know that when talking about borrowing in this business of online trading you are talking about leverage. You need to study more on leverage, equity, balance etc below

Leverage is going to be activated or set by you depending on your risk that you desire to take. The higher your leverage you are using then the higher your risk and chances of being knock out of your balance.
Short selling is sell, short or bear and that is when you analyse or predict that price will drop, you go on sell order.
Long selling is buy, long or bull and that is if you analyse or predict that price will increase, you click for buy order. I wish you the best you are on your journey.