Welcome. You can definitely contribute, everyone can really. If you want to help test, first get to trust level 1 (basic user) on this forum, and then follow the instructions for starting with Test 19 here (it also includes a link about getting to trust level 1):
To visit websites in SAFEnetwork all you need is the browser. See this topic for websites that are on test 19. To upload a website you use the Web hosting manager (see the Test 19 topic above).
Regarding safepress.io there is no development activity at the moment, but you can create a static copy of a WordPress website using a plugin and upload that. This would be nice for you to try and post a ‘how to’ if you like.