They constantly post the same job on LinkedIn, which is a strategy to promote their business, rather than really hiring someone. They ask you to include a cover letter in the application, and submit a case study about their website and business model. The process doesn't worth your time for such a small company and easy job, and I feel like they just wanted to get some free content through the interview process. Imagine if they always keep the job posted, constantly inviting candidates for interviews, and ask all of them to submit case studies, they don't really need any employees anymore! They can just get a lot of contents for free from the applicants. So I would suggest don't waste your time with them!