In the Author box HTML add this after author-summary closing </div>
<div class="author-icons">
<a href="url"><img src="url-to-svg-image"></a>
<a href="url"><img src="url-to-svg-image"></a>
<a href="url"><img src="url-to-svg-image"></a>
</div>
Then just add your links and urls to the images you want to use for your icons.
Might need a little CSS to tweak the icons eg.
.author-icons a {
margin-right: 0.25em;
}
.author-icons a img {
width: 30px;
height: 30px;
}