First, Vim doesn't support chording, i.e. pressing several keys simultaneously. It's only one main key, plus a possible combination of modifier keys (i.e. Shift, Ctrl, Alt). So, you'd type ", then +, then y when you read
For stuff that you do frequently, there's a shortcut mechanism, called mappings. For example, to use F2 instead:
:nnoremap <F2> "+y
You'll need to understand the modes of Vim.
:help map.txt has all the information. If you just want mappings like most Windows applications (e.g. Ctrl+C for copy), add
~/.vimrc, and you're done.
"+y so difficult? Well, usually you use Vim's internal registers, mostly the unnamed register, and that's the quick and easy
y. Vim is often used in the terminal or through an SSH connection, so interacting with the system's clipboard is not that common.