You enter the code of the First Pair exactly as it appears on your MetaTrader symbols , and same with second pair.
for example :
First Pair EURUSD
Second Pair GBPUSD
Some brokers add prefix or suffix to standard pair names, so EURUSD might be as EURUSDr, or EURUSDPro .... etc.
So symbols should be entered exactly as they appear in the terminal
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