For 2.0 themes that support app blocks, the Request a Quote button can be easily installed by navigating to your cart page when custom customizing your theme.
If you do not have any products in your cart, you may need to add some products so that you can see the checkout buttons and other cart information.
open up the section of the theme where you want the request a quote button to appear and select the "Add Block" button. Scroll down or search until you find "Quote Button by Quick Quote"
Once the button has been added to your page you can edit the visual appearance of the button with the edit panel on the right hand side of the page.
Be sure to save your changes when you are finished.