Step-by-step explanation:
I would recommend watching TV shows like "How the Universe works" or "Space's deepest Secrets".
so, if there were no gravity ?
no bigger bodies or structures would have formed at all. the universe would be one big "sea" of hydrogen atoms (and some helium and very few other atoms, whatever the Big Bang created by itself - depending on what the Big Bang really was, and if there really was such a thing) floating through the ever expanding spacetime.
yes, some tiny structures would have formed via electrostatic forces, and also via chemical reactions forming some larger molecules of atoms driven just by chance and the coincidence that atoms would even get that close to each other. but not many, as the larger atoms (like oxygen) can only be created by fusion of smaller atoms, which can only happen with immense pressure, which can only happen by gravity squeezing atoms together in cores of stars and such.
in other words, no black holes, no Galaxies around them, no stars in them, no planets and moons, no asteroids and comets around them would have formed.
the universe would be dark from the very beginning, just glimmering with the leftover background radiation from the Big Bang (or whatever it was).
there would be actually nothing to observe, literally.