How do i login to my Google website and add a meta tag or verify with google analytics?

Google recently made me a free website when I made my business page,but I need to verify site ownership and I have absolutely no experience with any of the behind the scenes stuff. Apparently i need to verify I own the site by adding html tag near the header,or I can use the google analytics account I just made,but I don't know how to sign into my domain to be able to add these tags. When I login my site from my google my business page it only gives option to edit business info,number,address,photos,content,etc... Can someone please explain me in a way that's easily understood how the hell to get into my site as the owner to add these meta tags??