Installation

Colorschemes/themes in Neovim / Vim need to be installed like any other plugin.

You can find them by doing just a google search or on vimcolorschemes.com.

You can use a plugin manager like VimPlug or Packer to install these colorschemes.

If you don't know how to install plugins in neovim you can checkout my post for installing plugins using VimPlug here.

Setting Colorscheme

After installation, you can use the colorscheme by using the following command in the command mode in neovim

:colo <name-of-colorscheme>

Making colorscheme persistent

To make it persistent even after you close and reopen neovim you can add the following line to the init.vim file

colo <name-of-colorscheme>

OR

by adding the following line in init.lua

vim.cmd('colo gruvbox')

Conclusion

Now you have successfully installed and changed your colorscheme in Neovim.