Switching from Blender Render to Cycles Render messes up everything

I’m a total beginner, trying to learn Blender to make a 360 degrees animation film for YouTube. I have to use Cycles Render because of the panoramic camera. I modeled everything and then noticed I was in Blender Render mode. When I switch to Cycles Render everything looks different, no textures or materials.
As far as I understood from googling - Cycles Render is a completely different engine and I guess I have to redo a lot to make everything look the same as in Blender Render mode.
Could anyone please suggest how to fix the issue, maybe there’s a tutorial somewhere with the steps needed to recreate everything? Or maybe I made some stupid mistake?
I attach the images in Blender Render and Cycles Render. Thank you!