HTML/CSS pt2 - embedding web fonts

i don’t understand the point of giving the same font family name in both face font rules for the normal and bold.

If i want to use normal font-weight i will give the name “opensans” but if i want to use the bold i have to give the font family property a different name like “opensans_bold”.

If i give the same name then how can i apply the bold font to a specific element.

CODE:
@font-face {
font-family: “opensans”;
src: url(“fonts/open-sans/opensans-regular-webfont.woff2”) format(“woff2”),
url(“fonts/open-sans/opensans-regular-webfont.woff”) format(“woff”);
font-weight: normal;
font-style: normal;
}

@font-face {
font-family: “opensans”; - SHOULD BE A DIFFERENT NAME???
src: url(“fonts/open-sans/opensans-bold-webfont.woff2”) format(“woff2”),
url(“fonts/open-sans/opensans-bold-webfont.woff”) format(“woff”);
font-weight: bold;
font-style: normal;
}

Thank you for the attention

Waiting for your feedback

Best regards,
Kévin Mateus