The entry price is the price at which a position/trade was opened.

For example, if you go long on (buy) bitcoin when it costs $8,300, then your entry price is $8,300.

The % gain or loss is compared to the entry price. So if the price goes up to $8,500, the unrealized gain would be 2.4% (8500/8300). If the price goes down to $8000, then the unrealized loss would be -3.6% (8000/8300 - 1).