I need advice with os

Ya know, it's pretty easy to google that and find a thousand usable answers
My first suggestion is to start from a blank drive that has no operating system installed. This is mostly because all the Windows versions seem to fail when their partitions are shrunk. Once you have a clean slate, so to speak, I would install whatever build of Windows you fancy, but during the installation, do not format the entire drive but manually create a partition for Windows to be installed to. Obviously you will not want this partition to span the entirety of the hard drive (else you will not be able to install another OS), so make the partition some good percentage of the overall size of the drive (because Windows always consumes more storage space than most Linux distros). I think Windows will require at least like 20GB to install, but don't quote me on that
Once you have Windows installed, go ahead and boot to it (should be done automatically) and update it and do whatever you need to do. If the install seems fine - Rejoice! You are half way done.
Next you will want to download the latest lubuntu live installer iso from their website and install it to either a CD or to a flash drive (with something like Unetbootin or Rufus). When that is complete, insert the installer media to the device you want to install lubuntu to and boot to the installer media. You can change boot order in BIOS to accomplish this or just select it from the BIOS boot menu (which should summoned from the F8 key). When you load up the live installer for a Linux distro, you are greeted with a small but workable desktop environment that represents the shell of the OS. Find the option to install lubuntu and, like with the Windows install, do not let the installer write to the entire drive (which would wipe the Windows partition!). Instead, create your own partition(s) for lubuntu that occupy whatever part of the drive is not occupied by Windows. When the install is complete, you should boot immediately to lubuntu upon restart (because lubuntu should have overwritten Windows' MBR).
In order to flip between both OS's, boot to lubuntu and install a software called GRUB2. GRUB is a really cool universal bootloader that allows for, theoretically, infinite OS installs, much less two. To install GRUB2, I suggest installing yannubuntu's boot-repair software, running it, and letting run normally. boot-repair will probe your disc for other operating systems and will recognize Windows, and will add Windows to the GRUB2 bootloader. So the next time you boot, you should be greeted with a menu containing a list of all of the OS's on your hard drive and will allow you to select one to boot to. Both Windows and lubuntu are now available to boot to and are not dependent on one another (unlike a virtual machine). If you want to edit the GRUB2 list or even decorate it, there is a software known as GRUB-customizer that can help with that.

Again, there are a thousand guides online, and the method I described is just one that works for me. Good luck!