Where should I look for perl 6 libraries?
When I've chosen one, how can I add it to my perl 6 project?
Use zef to install it on your local system.
Read the modules doc page for directions on
useing a module in your project.
If I find it [somewhere], how can I add it to my perl 6 project?
If zef can see it (and zef will usually be able to see a module if its repo is listed at modules.perl6.org) then zef should be able to install it. If not, contact the author or ask about it on #perl6.
As an answer to point 2) and 3) , you can take a look at
6pm. It's idea is to be NPM for Perl6. It works over
$ 6pm init
# Install dependencies to ./perl6_modules and add it to META6.json
$ 6pm install Test::Meta --save
# Run a file using the local dependencies
$ 6pm exec-file test.p6
# Make your code always use 6pm by making it "use SixPM;"
$ perl6 test.p6
See the full documentation for more information.