How can I download adobe reader on macbook pro 10.7.5

I have a Macbook Pro OS X Lion 10.7.5

Processor Speed is 2.4 GHz

Memory is 4 GB

Don't know Storage Capacity

My Problem is after downloading the Adobe Reader I press "FINISH" and the download seems to disappear. So I didn't press "FINISH" after one trial and it seems to be there but won't open.

How can my download be successful?

Thanks

Sandra