Hello! I hope you enjoy it here, congrats on your first post! You can apply to tests by going to a post that interests you and applying by clicking the image (sometimes an image of a broken icon) or clicking the links, don’t forget to read the requirements the designer set before applying 
Something I do for newcomers when I can, if you ever need help never hesitate to ask in the community, if you need immediate answers feel free to use the help center, search in the community, or the wiki [link below] and community guidelines if needed the testing guidelines may also prove helpful. Happy crafting! Hope to see your crafts soon as well