https://fonts.google.com/spec.:400,500,500i,700

https://fonts.google.com/specimen/Ubuntu?selection.family=Ubuntu:400,500,500i,700

I choose Ubuntu
and then I check regular 400
and I introduce it to the web site and write it like this

font-family: "Ubuntu", sans-serif;

but I want the word regular 4000.I have
but how to change the default to Medium?
and how to change it to regular?.