How do I insert the FBW A320 cockpit into a plane converted from FSX?

Hello, So basically I inserted a plane from FSX using the legacy importer and
I am interested to insert the flybywire a320 cockpit inside of it. Thanks!

I would strongly advise against this, as the A32NX is in constant development
and will often result in breaking changes when trying to “merge” it with
another plane. Furthermore, keep in mind that the FSX converted aircraft may
have its own copyright license or EULA which prohibits this, or is
incompatible with the GPLv3 license FBW uses.