once i install a mod how do i put it into the game
and would you suggest this mod http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=7766

You can find answers to your questions regarding this in the pinned thread *** http://www.gamesas.com/index.php?/topic/106063-morrowind-mods-faq/ *** on this forum's first page.

that is way too confusing for me

You did see the section on http://www.gamesas.com/index.php?/topic/106063-morrowind-mods-faq/page__p__1772866&#entry1772866, right?
Well, that's as simple as it gets.
There isn't a way to tell you how to install a mod that wouldn't be the same description as what's in the FAQ.

http://www.youtube.com/watch?v=yeWjRlNAj60&feature=related

Google and Youtube. Endless knowledge/information and so on. :goodjob:

Well, I'm the creator of that particular mod so my opinion on whether or not you should download it doesn't really mean squat . Just thought it'd be good to point out that the mod is currently in the beta testing phase so it definitely has its kinks. According to my official beta testers however everything seems to be working except for two things. The forced transformations are only working some of the time rather than all of the time, and the player controlled howling doesn't always work in interiors. Both of which have been fixed for the next version which I'm trying to get out asap, but I still have a lot of work to do before another release. With that said, if the features in the mod description look interesting to you I'd say give it a try. You can always simply remove the mod if you don't like it. Otherwise just pass it up and move on to something that matches your likes better.