I cannot give you a comprehensive set of instructions, the basic process is described here (some terms might be different by now):
Basically, if there is enough free space on the built-in storage, you can save your SD card data there. If you need more space, you can connect your FP3 to a computer (with hopefully enough space left ) and transfer the remaining data that way via “file transfer”.
) and transfer the remaining data that way via “file transfer”.