I think most of us have a hard time finding anywhere to plant.
If you’re not a landowner, you’ll have to volunteer somewhere, but I’ve looked it up before and there aren’t that many opportunities in my country. The organization in charge of national forests has their own staff for it.
Ironically the best way to get into it here is to join a specific local fuel station chain’s “donate a cent per liter and we match, every 25 cents is a tree” community, which occasionally reaches out to members to help plant all the trees they’ve received donations for. So the easiest way to get to plant trees is to… buy fossil fuels???
To be fair, public spaces in my country already have loads of trees in most places. In my city, there’s a park that doesn’t get mowed because they’re letting it grow into a grove. The trees are also very tall and healthy. It’s goddamn beautiful. Incidentally it’s also part of my commute whenever I walk (which depends on how early I manage to wake up, really)