Please excuse me, I tried to figure out what the problem might be for you, but couldn't. If you could talk about what problem you have, what you want to do but can't or ask for something you don't know, would be more clear. In this case here and now, there is no way to understand what problem you have because everything seems to be right. I think so because I currently have two Dell, one Vostro and one Inspiron (released in 2019), so basically the same. If someone else understands your problem, he/she will probably help You, but I need more specific question, because tutorials about using legacy and UEFI, MBR and GPT have been written thosands already. PS. In future try to be more accurate, in Your post is several mistakes, I don't know if they are really spelling mistakes or something else.
I am extremely sorry for my mistake. I have a Dell Inspiron 7559 laptop, the BIOS has the interface shown in Figure 1 from the time I bought it. Then I switch Boot Legacy (Default) to UEFI & convert hard drive from MBR to GPT. Next I installed Windows 10. From then on, my BIOS changed from Figure 1 to Figure 2. So I want to go back to the BIOS as shown in Figure 1 PS: Forgive my poor English