I have read that an .ipk file is installed via manager opkg. However, I do not have this software on my computer and I don't know how to install it. Is there some other option to install this kind of files? Thank you
You can build opkg (./configure, make, make install) on your debian system. The opkg git repo is at http://git.yoctoproject.org/cgit/cgit.cgi/opkg.
Ipk's and debian files are really similar. If your ipk doesn't have any dependencies, you could also try to install it directly via dpkg (change it's name from .ipk to .deb). Be aware that depending on the ipk this may or may not work.