need help placing "badge" in sidebar

hello, i hired someone to create a blog and i hadn’t had the time learn how to maintain or upgrade it on wp. (now, i’m looking to learn and i know i prob should upgrade my site as well.)

meanwhile, there is a charity web event for japan relief that i’d like to help promote by posting a badge (i created) w/ a link to the event site. will someone kindly explain the steps or point me to a link?

fyi, here’s my blog: https://www.cabcabinmoran.com/blog/

thanks, in advance…
e.c.moran