smh008 Is this migration from F5 to F5 or from another vendor to F5? If this is F5 to F5 you can go to the CLI and use the list ltm command and other list commands to gather the data. Once you have all the command output you can put them into one flat file and save that file to the /shared/tmp directory. Please keep in mind that the list output will most likely have created on, last updated, and index numbers in the configuration output and that will have to be removed because it could cause issues with existing configuration. Once you have that file you can run the following command to create the entirty of the configuration. Do not forget to add on merge to the end of the command otherwise you could erase your current F5 configuration. Once you have that configuration in place you can sync your F5 BIG-IPs to the BIG-IQ and ensure that you resolve any conflicts by using the F5 BIG-IP configuration and not the BIG-IQ otherwise you will erase your BIG-IO configuration and replace it with the BIG-IQ configuration. Sadly the BIG-IQ doesn't really make massive amount of configuration changes easily unless it's a shared configuration which usually isn't virtual servers and what not. If this is not coming from many BIG-IPs to one BIG-IP and it's a different vendor you will have to use some scripting to parse through all your data to get it into the correct format.
load sys config file /shared/tmp/<name_of_file> merge