Markdown - Open links in a new tab

Site URL: https://www.bfsbuilt.com

I am trying to create an accordion (expandable section) to list vendors our business features, with each vendor listed linking to their website. Using this tutorial I have built the content out (https://www.itssevenone.com/tutorials-for-squarespace-71/accordion), but now I cannot get my links to open in a new tab. Each time I select this setting through the hyperlink options in Squarespace, it continually reverts back to opening links in the same tab. 

Try using jQuery in this guide.