Actually it does not matter which platform should be launched first.
The only exception - if you want to copy orders from Source to Receiver account, which were opened before Forex Copier installation.
In this case, before launching the platforms please click “Settings” on Receiver account, go to“Filtering orders” tab, click “Ignore some orders from Source account” and increase the values of
“Max difference between Source open price and current Market price” and “Ignore orders which were opened … minutes ago or earlier”.
Then save new settings, click “Apply Scheme” button and launch MT4 platforms.