Make sure that you have your character selected in the scene.
In the Content manager tab select Project > Character > Custom.
Open either the Base or Clothed folder depending on the character and then click on the + in the lower panel bar.
Give the character a suitable name once added.
Open a new Project and navigate to the folder containing your saved custom character.
Double click on the saved character and select what you wish to do with it when the message window opens.
Gerry
System: Win 10 Pro (21H2), Asus X99-E WS, CPU i7-5930K -3,5 GHz, 32 GB DDR4 2666-16 RAM, NVidia GTX 1080 Ti GPU - 11 GB VRAM(Driver Studio-536.99), Samsung 850 Pro 512 GB SSD, 6 TB HD storage.