Render help

I am new to blender. When I save my rendered work and try to open them in blender I get a blank grey screen with grids on it. It won’t open anything.

Are you trying to load a 3d scene document (.blend file) or are you trying to load an image that you rendered?

Normally you create your scene and save it (in a .blend file) and that’s what you later load if you want to continue working on it later. When you render, you usually produce a 2D image (or series of images as an animation) that shows up in Blender’s image viewer and which you can then save from there (or have the render output to disk directly) as something like a .png or .exr file, but you wouldn’t usually later load those image files back into Blender (except in special cases).