Can you get a DVD-R disc? If you can, you can download an OS and then burn the OS onto the disc. Your computer needs at least 8 GB or maybe 20 GB free for Ubuntu as it is a larger OS. You may want to put Ubuntu on your PC or you may want to try an OS that is smaller than that.

Three Steps

Here are the 3 steps to installing Wubi: you can see these steps in the video below:

First, you can download Wubi (Ubuntu for Windows) here:
https://github.com/hakuna-m/wubiuefi/releases

Second, you can make a partition (drive) with the Disk Management program on Windows: you can see this in the video below:

Third, you can install Wubi into the new partition (aka drive), not into the C: drive but a different letter, maybe letter E drive

You can read the comments below this video on YouTube as well. You can download and install Ubuntu without a DVD disc or thumb drive. You can install Ubuntu 16.04 or Ubuntu 18.04 or another OS. I like and I have Ubuntu Mate 16.04 on my laptop. You may not have to make a new partition on Windows. Making a partition is like making a new room in your house, in your computer. It might be more dangerous to not make a new room, a new partition, but some people skip that step.

Skip Making a Partition?

You can take it one step at a time as you learn how to do these things, if you want. There are different operating systems you can install, like I said, AKA different distributions (distros), AKA flavors, versions, of Ubuntu, like I said. There is Ubuntu, and then there is Lubuntu. Then there is Kubuntu. And there is Ubuntu Mate. And there is Mint.

Distros, Flavors:

And there are others too of Ubuntu. Different flavors, different versions of Ubuntu, and some are smaller than 8 GB and some might be bigger. And Ubuntu is from the Linux family. So, there are other Linux OS out there as well. If you like Windows, you can install Ubuntu 18.04 and then you can have Ubuntu and Windows, both of them, on your computer.