And just to clarify,
- To check which way the normals are facing go into edit mode and click on the “display face normals as lines” icon under mesh display on the right hand menu of the 3D viewport window.
- To fix the normals go into edit mode and click on “flip direction” to flip the direction of any normals you have selected. Alternatively, click on “recalculate” to have Blender try to figure out which way all the normals should face on its own. Both options are in the “Shading/ UVs” tab in the left hand menu.
Cheers,
-Noah