16.04 - How to set grub as the boot manager?

I recently bought a new HP computer, it is running on Windows 10 and I installed Ubuntu 16.04, but everytime I turn on the PC it goes straight to Windows, so how can I fix this to set up grub at the boot time. I can access Ubuntu from Windows Advanced Restart settings, but that's the only way. I have disabled the secure boot on the bios and the fast startup for Windows but it didn't work.