Is it possible to add a sales tab linked to a mailing list popup? Dawn theme

[Gen-Audio]

Hi,

I was wondering if it is possible to achieve a sales tab that links to a mailing list like this site for example:

https://amoss-store.com/ 

It has a red tab on the left that opens up when you click on it

My website: www.generationaudio.co.uk 

Thanks in advance

[SMITH23]

here is the topic to do

[SMITH23]

this is awesome i think

[Gen-Audio]

??????

Sorry but that doesn't make sense