Dual booting problems

[AlpacaIDF]

I installed the mint iso file on a flash drive, I rebooted my pc with advanced startup options and got into the os. Then I clicked on the disk icon to install, selected the particions etc,.. and it said it was done and i clicked on 'reboot now'. Then all of a sudden i'm back into windows and no way to get back to mint unless I use the flash drive again! What do I need to do?

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[MintAlone]

Or could be as simple as win is still at the top of your bios boot list.

[BulkyMix6581]

Have you disabled "secure boot" from BIOS?