A basic example:

parameter1 = optimize(....);
parameter2 = optimize(....);

asset("EUR/USD");
trade(parameter1,parameter2);

asset("AUD/USD");
trade(parameter1,parameter2);

asset("JPY/USD");
trade(parameter1,parameter2);

... etc.

Instead of the repeated asset/trade calls, a more elegant way is using an asset list, a for() loop, and a switch() statement.