User journey, work flow: thinking about the UI/UX for new user

This ticket covers 2 points:

1. the order of blocks on a group landing page (see # 3345220 📌 Side bar blocks order: thinking about the UI/UX Active )
2. the order of blocks on the Localize home page:

for the second point, here's a proposal for changing the display of the home page to highlight the contribution instructions:
1. move the "how to contribute" section up into the main section of the page
2. move the "Set up your group" section back into the main section of the page, in the form of an accordion.