Meshes Imported from Blender Problem.

Hello guys, I have been using unreal and blender for almost 2 weeks now so I dont really know most of the terminology.
I have come across a problem when importing meshes from blender to unreal. My problem is that I have created a mesh in blender
and when I switch to edit mode it looks ok ( I think)(image1), I export it as a FBX file,but when I import in unreal i get 3 messages:

1=no smoothing group was found in this FBX scene (I have searched how to fix this but could not)
2=cube has degenerate tangent bases (could not fix this either)
3=has some nearly zero bi-normals (not fixed)

When I ignore these messenges and drag and drop the mesh (it has 5 different meshes) and then add materials on it
the material looks stretched(cant find a better word) and sometimes it trembles. (image2)

Could you please help me find a solution to this problem, I started a project for fun but I am really into it as the time goes by
but I cannot continue because of this problem.

As I said, I dont know the terminology yet and english is my second language, so if you have an answer write it step by step
as if you are talking to a child, for example “right click then click edit…etc” or if you have a tutorial video which can help.

Thanks for your help.

It seems like most of the problems have been solved but there is something new happening as you see in the images. Because I didn’t know how to make the shape of this column thing(don’t know the word for it) I created it like this:

I created a sphere and then extracted and scaled down its edges again and again until it looked like you see in the picture. It doesn’t look that bad for what I want to use it but when I import it to unreal some of its faces dissapear. I have tried exporting it with different export options at the export tabs like geometry, but it I cant fix it.

The only solution I was able to find was duplicating it then rotating it 90 degrees and join them together, but as the second friend replied,the mesh flickers.
Thank you so helping.