Is it possible to install the software on the computer without internet? Do I need to train the software manually?
Not directly, no. The install process needs to Download several GBs of data, which it is not realistic for us to package.
You could install it on a different machine and then transfer the faceswap folder over.
You would need to install MiniConda3 on the other computer too (and then also transfer the faceswap Conda environment over).
You would also need to download the required models for running extraction (as these are downloaded by the application when they are first required)
My word is final