Seems like the easiest way for most people to help out is in the Marathon.
This involves downloading BOINC, selecting the "World Community Grid" project, and then selecting the sub-project "OpenZIKA".
1. Download + Install BOINC (https://boinc.berkeley.edu/download.php)
2. Open BOINC and click "Add Project"
3. Select the "World Community Grid" project, and then click on their website url. (https://www.worldcommunitygrid.org/discover.action)
4. On their Website, click "Join Now" at the top left or right depending. Enter your information and Register.
5. Once presented with the Sub project selection, choose "OpenZIKA" and click next. It will download a program, but you don't need it.
6. Go back to the BOINC app and click "Next >". Login with the World Community Grid account that you just signed up for.
Your BOINC app will now benchmark your system, and then start running.
BUT, you still need to set your team to the LTT forum one.
7. Navigate to the team selection page, and login if you aren't already (https://www.worldcommunitygrid.org/ms/team/viewMyTeam.do)
8. Type in "LinusTechTips" in the "Contains:" field.
9. Click on the "LinusTechTips_Team" result that shows up. Once the page loads click "Join Team".
You will now be BOINCing for the LTT team
This is the easiest way to help out the cause, but there are more beneficial / advanced ways to do so if you're interested. Refer to the OP for more information.
Message @Ben Quigley if you need assistance.