Trade price in backtest

Hello every :

my database is in tick interval , and i set the aux1 is buyprice , aux2 is sellprice

if in my afl i want to set in backtest the trade price is next tick if buy set price is aux2 sell set price is aux1 hwo do i do ??

tks alot

Look at the built-in variables named BuyPrice, SellPrice, ShortPrice, CoverPrice.