Welcome to the forum!
For the first question, please do the platform tutorial.
For the second, read 'how events work' in the manual, and then 'picking'.
Also search the FAQ and the forum itself.
Generally it helps a lot if you can provide your .capx (project) or at least a screenshot of what you've tried.
These questions get asked every day.. you will get more respect (and more help) if you do some reading first. Good luck