How can I use free files that Envato gives every month?

Hi! I’m quite new on this platform, so can anyone please explain how can I use free files that Envatio gives every month? I’m planing to elevate my skills with a project (unpayed) for the company my brother works for. I’d like to use some music and maybe some graphic I downloaded earlier as a freebies of the month. For how long I can use them? Can I use them only if I release my project during that month Envato gives those free files or I can download those files and use them later? Also, what sould I do if I got copyright claim on Youtube for those free files?