It is always important to pursue both personal goals and collective actions, as the combination of the two will be even more effective in driving change.
Looking for community-based initiatives such as beach clean-ups or recycling schemes can be an easy way to start, as you can meet like-minded activists. Voting and lobbying are other ways you can get involved. This will let your local policymakers know your environmental concerns and help to initiate systemic change.
Addtionally, you can learn about climate change and required actions by taking online courses at sites like edX and Coursera. Participating in webinars with other activists can also give you opportunities to exchange information. While we all have to deal with COVID-19 restrictions, we can still raise awareness of the issue online.