How Removing/Installing Shower Base on Concrete

Hi,

I'm thinking of reno my shower this Easter and I'm clueless
I can removed all the cement sheet and tile on the wall and the shower screen but I to scare to remove the shower base?

Here is a picture of my current shower. Do I unscrew anything before destroy it or lifting up the old base with a jack? How do I remove it properly what are the steps please????

Once I removed the old base how do I reconnect the plum back with the new base since all around the shower is concrete?
http://www.jigsawpuzzles.com.au/showe002.jpg