How to dual boot your PC

So, you want Linux on your PC which is currently running Windows. 10 maybe? But you don't want to let Windows go. It's too familiar and comfortable. In this case, the best option is to dual boot.

Here are the steps to dual boot a Windows PC with Ubuntu Linux. The first two are independent steps. You can follow them in any order. But once they're done, the rest should be in order.

Step 1
There's a high chance that your PC will be in UEFI Boot mode. You will need to disable secure boot to boot from a flash drive and might also require enabling legacy support. Pressing either of F2, F12, F10 or esc during start-up will do the trick. Most likely you'll see an instruction saying something like 'Press esc for startup options' right when you press the power button. Some manufacturers also include a dedicated button for start-up options. Using the arrow keys, navigate to 'Boot Options' under 'System Configuration' and press Enter. Now go to 'Secure Boot' and disable it. Similarly, go to Legacy Support and enable it. Select Save and Exit (F10 for HP, might be the same for others too). Your PC will now start normally in Windows.

Step 2
Make a bootable USB drive. For this part, I'm assuming you already have an ISO file of Ubuntu. If not, you can download it from their official website.

Here, you'll need an application, Rufus.

Download and run the .exe file (no installation required)

You'll see a window like this:

Select 'ISO image' as circled in the picture and then select your .iso file by clicking on the icon beside it. Device should show the name of the USB device currently connected. Keep the rest as it is.

Note: clicking on start will erase all the data presently on your device, so be sure to take a backup.

Once this is done, you're set to start the actual installation!

Step 3

Restart your PC and go start boot manager. It's the same screen you went to for enabling legacy support.

But now, instead of BIOS options, go to Boot device options or something similar. You'll be asked the device from which to boot. The flash drive with Ubuntu ought to be visible here. Select that.

Note: Select the drive in the BIOS you have Windows. Or else you'll be losing it. Normally it'll be UEFI. 

This point does make me feel installation might work without even enabling Legacy support. But everyone suggested doing it and it doesn't really hurt. 

Step 4

You'll now be seeing a screen with several options like 'try Ubuntu without installing' and 'install Ubuntu'. Choose try 'Try Ubuntu without installing'. The Ubuntu desktop will open. You familiarise yourself with the OS. Setup a Wi-Fi connection. There will be an option to install on the desktop. Select that when you're ready. 

Step 5

So you've selected to install now. First, you'll be asked your choice of language. After that, you'll see a window with check boxes for 'download updates while installing' and 'install third party software'. I suggest you check both. Next, it will check for installed operating systems. You will get a message saying something like Windows was detected, select action. It will ask whether you want to erase Windows and install Ubuntu or install Ubuntu alongside Windows. Choose the second option. 

Step 6

You'll be asked to partition your hard disk. A visual representation of the partitions will be visible. It will show some arbitrary space assigned to Ubuntu. You just have to drag the separator between the two partitions on your screen to change the size. Once you're done click on install now. This step takes some patience as it takes quite a lot of time to partition your hard disk. After that, it's a cake walk. Go watch a movie. Ubuntu will be ready for you by the time you're back!