Please can anyone help?

Just bought a second hand macbook pro 2017 and went to factory reset, had to manually delete files and did so. Now just getting the flashing question mark screen, everything online says to reinstall macOS but there's nowhere to physically install it, it just shows this on screen I'm honestly on the verge of tears, I use macbook everyday for work and my macbook air 2022 screen just broke on me and I can't afford to get it fixed right now, please can someone reassure me this is fixable Bought from a friend for £300 and showed me it worked fine so is definitely something I have done in the reset process