I usually export 3-5 maps from Painter. Metallic, BaseColor, Glossiness (choose Roughness if you have your corona material set to Roughness, which is the default setting), Normal and height (height would be displacement in Corona)
First, check what your shader settings are inside Painter. Do you have Metallic, BaseColor, Roughness Normal and height channel there? If not, change it. There are already templates from which you can choose from, check it out when you start a new project.
Second, change inside Painter the export settings according to your needs. If I'm remembering correctly, there is even a Corona template. If not, you can choose another on, that has these channels I described above.
The only thing that could go wrong is the normal map, because there are two options. So check in corona if the normal map gives you the correct shading.
If the shading looks incorrect, you can either flip Y inside of Corona Normal shader, or change the normal map in the export settings of Painter.
