Open multiple info buffers in Emacs

Help for the info command says (get help with F1 f info):

A numeric prefix argument selects an Info buffer with the prefix
number appended to the Info buffer name.

So, open a first info window as usual, then open another info window by typing (for example):

M-2 M-x info

Now you have 2 independent info windows, the second one called *info*<2>.