So how would I put the link button Print this out!
under the table?
could I customize it according to my own design by using CSS?
Simply write it under the table component would be good enough
<div>
<ComponentToPrint ref={el => (this.componentRef = el)} />
<ReactToPrint
trigger={() => <a href="#">Print this out!</a>}
content={() => this.componentRef}
/>
</div>