Walaikum Assalam, it's not necessary to have 7 gigs but it creates more opportunity to get your very first order. You can't participate in a skill test manually rather Fiverr will ask you to do a skill test while publishing a gig relevant to the topic. Try to be more active on Fiverr. And share your gigs on effective social media platforms like LinkedIn, Twitter, and Instagram. Good luck to your new venture!!