ive bought a ebay short shifter and i wanted to know how do i install it?

first the nylon peice is way too big and wheni put the rest of it is kinda loose

 

Your first mistake was buying an Ebay shifter. No really, as long as it was the correct model shifter it should work with a little modification. Mazdatrix has a video on their website on how to install their shifter which should show you all you need. Do a search and I'm sure you will find something.

 

Unscrew shifter ****. Remove plastic shifter surround (pries up on 4 corners). Unbolt shift boot retainer (4 bolts). Remove shift boot. Unbolt shifter (3 bolts).

 

You'll need to machine/grind/sand the bottom nylon bush (goes into the shifter rod block) to fit.
You will probably also have to shim the upper and lower bushes for the seating ball (look in the plumbing section of your local Ace for a selection of washers) so the unit fits nicely.