Bdtyktl

I have installed Virtualbox but I am total newbie of this directory hierarchy. Now I can't find it. The downloaded file is:
virtualbox-5.2_5.2.22-126460_Ubuntu_bionic_amd64.deb. After executed it by double click it installed Virtualbox. Now where should I search for it? Whit find -name "virtualbox*" I can find it in more than few folders:

./var/lib/dpkg/info/virtualbox-5.2.templates

./var/lib/dpkg/info/virtualbox-5.2.postrm

./var/lib/dpkg/info/virtualbox-5.2.list

./var/lib/dpkg/info/virtualbox-5.2.prerm

./var/lib/dpkg/info/virtualbox-5.2.preinst

./var/lib/dpkg/info/virtualbox-5.2.postinst

./var/lib/dpkg/info/virtualbox-5.2.md5sums

./var/lib/app-info/icons/ubuntu-bionic-updates-multiverse/64x64/virtualbox-qt_virtualbox.png

./var/lib/app-info/icons/ubuntu-bionic-multiverse/64x64/virtualbox-qt_virtualbox.png

./usr/bin/virtualbox

./usr/lib/virtualbox

./usr/share/applications/virtualbox.desktop

./usr/share/pixmaps/virtualbox.png

./usr/share/lintian/overrides/virtualbox-5.2

./usr/share/mime/packages/virtualbox-5.2.xml

After ton of post and article I am totally discouraged about this Linux installations... Where should I search for the .exe file. ( I know it is not an .exe extension in Linux )

I assume that you are trying to start VirtualBox: press the Super key (also called the Windows key) and type "virtualbox" - the icon for launching will appear.