What is it?

This youtube video should give you some idea of eye piece types and sizes and their benefits.
How to Use Telescopes Telescope Eyepieces

You should be able to use the instructions for a typical refractor type telescope. Try this site.
Support Manuals Meade Instruments

Can you focus on a distant object during the day time? Do you still have the "diagonal" if this is a refractor style telescope? This is a diagonal it goes into the focuser and then the eyepieces go into the diagonal. Put the eyepiece with the largest number written on it into the diagonal and practice focusing during the day time. DO NOT USE the 2x barlow if you have one.

http://www.amazon.com/b?ie=UTF8&node=3426071 These are diagonals.

Contact Toys R US that sell this telescope-- or use either www.stellarium to control the scope.

www.stellarium.org

The disk is not actually needed it is just a planetarium software like Stellarium. All the goto controls are inside the hand controller.

You must use the eyepieces--

Put the eyepiece with the largest number written on it into the telescope. DO NOT use the 2x barlow if you have one.

Practice focusing during the day time on a distant object. Read my tips on my profile page.

Reflector style telescopes DO NOT need a diagonal. The eyepiece goes directly into the focuser.

Have you used the telescope with just the eyepiece? That is all you need.

You did not say WHICH Edu-Science telescope you own.

However, put the eyepiece with the largest number written on it into the telescope focuser. You can use the small mirror diagonal if you have one-- depends on the type of telescope.

DO NOT use the 2xbarlow if you have one just the eyepiece with the largest number written on it. Take it outside during the daytime and practice focusing on a distant object at least 300 feet away.

You will not find a manual for that telescope which is sold by Toys R Us. However Meade and Bushnell both maintain web sites with all of their telescope manuals--- here:

http://www.meade.com/manuals/index.html Meade manuals

http://www.opticsplanet.net/bushnell-warranty.html Bushnell

Look around the web sites under the REFRACTOR heading for one that is similar to your telescope. They all assemble and are used the same way.

Read my TIPS on my profile page and also read this web site:

http://www.texasastro.org/telescope.php

The end with the focuser. Then put the eyepiece with the largest number written on it into the focuser. I believe this model is a REFLECTOR, if it is there is a mirror in the bottom of the scope.

REFRACTORS have a lens in the front of the scope.

See this:
http://www.texasastro.org/telescope.php

Then read my Frequently Asked Questions TIP on my profile page. The picture you selected shows a REFRACTOR telescope.

You will not find a manual for this scope -- sold by Toys R Us by the way.

However Meade telescopes maintains a web site with all their manuals. REFLECTORS all go together in a similar fashion. Look on the web page below under REFLECTORS for a manual similar to your telescope.

http://www.meade.com/manuals/index.html

maybe this one???
http://www.meade.com/manuals/TelescopeManuals/Reflectors/062002Jupiter114EQ-D.pdf

You mean the focuser end? I suppose?

You will not be able to order a "part" but you might be able to find a complete new focuser assembly. Here:
http://www.agenaastro.com/Crayford-Focusers-s/140.htm

But notice that a new focuser probably costs more than the entire telescope! It may also be possible to straighten out the lip by taking the scope to a metal shop -- or car body shop.

You can try calling the manufacturer, but I doubt they will be able to get you a new focuser at a reasonable price-- compared to the total cost of the scope.

Next time do not buy a telescope from Toys R Us. Read my telescope buying TIPS in my profile.