MIDI keyboard on Logic Express 8

Hi there, this is my first post.

I appreciate my question may well have been asked before, but I was hoping to be able to get a new conversation flowing - That way, you might all be kind enough to answer my questions as we go along! Hope that's ok!

I've got a brand new iMac (not sure if this is relevant, but it's OS X version 10.5.4, 2ghz Intel Core 2 Duo) with Logic Express 8.

The midi keyboard I have - "Evolution eKeys" - is being recognised by Logic - Things happen when I hit the keys. But there is no sound coming back out.

I've tried this: http://support.apple.com/kb/HT2851?viewlocale=en_US

....but it hasn't helped.

I have only had the iMac for 2 days, so if anybody could help, could I please ask that you write in VERY basic terms? I would appreciate this so much!

It's stressing me out

Thank you all. I would really appreciate your help.

 

Hello and thank you ever so much for your reply.

I'm not sure what a "softsynth" is... would you be kind enough to explain how I go about making one?

Thank you!