If I buy a laptop and the Win10 trial is already installed - is it normal that I can't get out of BiOS?

The question is actually already above. I bought a laptop without Windows 10 full version, but the trial should actually be installed anyway, according to the manufacturer. Have already asked and wait for an answer, but maybe it's up to me? Does anyone know?

There's no trial version. Windows 10 is also running without activation, however, it is constantly activating and a few functions do not work.

Download the Windows 10 Mediacreation Tool from Microsoft and create a bootable USB stick with it, plug it into the computer and say in the BIOS that the computer should start from the USB stick. The installation dialog follows.

This has nothing to do with Windows. - If you do not get into the BIOS, this is usually because the wrong key is pressed when you start the PC.

How to open the BIOS is usually in the user's guide of the laptop.