Yes, you can set a stop-loss and limit sell at the same time on Coinbase. This can be helpful if you want to limit your losses on a trade, or if you want to ensure that you sell your crypto once it reaches a certain price.
When setting a stop-loss, you will need to choose a price at which you want to sell your crypto if the price falls below that level. You can then set a limit sell order for a price above the stop-loss price, which will ensure that you sell your crypto once it reaches that level.
If you are new to trading cryptocurrencies, then it is always best to practice with a demo account first before putting any real money at risk. That way, you can get a feel for how the market works and learn how to set stop-losses and limit orders without losing any money.