Pair refers to the asset you are trading and the asset you are measuring it against during the trade. For example, if you are using the Bedrock Trend Bot then you will be trading the price of Bitcoin in terms of USD. So the pair this trading algortihm will be using is BTC/USD.
Entry Price refers to the price at which point you entered the trade.
Last Price refers to the most up to date price from the exchange you are executing the trade from.