First check whether the file system is MBR+BIOS or GPT+UEFI. Nowadays, most computers are GPT+UEFI, so we only talk about GPT+UEFI here.
Download Ubuntu iso and make a U-installer using rufus. When using rufus, notice the option of GPT+UEFI.
Start the computer from U-installer. The most important thing is making a proper partition for Ubuntu. At least make three partitions: / (ext4), swap (2G), reserved for UEFI (1G). If necessary, make another partition /home. Note that ubuntu UEFI should be on the same disk as Windows UEFI.