First of all, flush it out very thoroughly with clear water. If it won't flush let it sit for two or three days with the nib submerged in plain water - not the whole pen, just the nib. Pens are made to keep ink in, not to keep water out. You don't want water seeping in and rusting the innards, if you can help it.
Then after you've soaked it throughly, flush again. Water is your friend.
If water alone doesn't do it, put a couple of drops of ammonia in the water. About three drops to a cup of water. Not Windex. That's got other chemicals in it that are bad for pens. Flush that till the no ink is apparent.
I dry out the insides of my pens at this point by sticking the nib down in to a roll of toilet paper, with the nib between the sheets of toilet paper. This works well for me to draw out the left over water. If there's color left on the toilet paper, you haven't gotten all the ink out. Flush again.
I would not suggest that you take the pen apart unless you've flush thoroughly and you're unhappy with how it writes. Then maybe you need to take it apart and clean the feed and nib. Taking them apart isn't all that difficult but, given your novice position and the fact that you seem to want to keep this pen (and not break it), I wouldn't suggest taking is apart unless you just absolutely have to.
Remember time and patience are your friends. Water is your friend. This is a multi-day process since you're working on dissolving solids in little tiny spaces and you're relying on osmosis to facilitate this process. Osmosis is slow.
NEVER EVER use India ink.
Most any ink made by a fountain pen manufacturer would be fine. I really like the people at Pendemonium.com for purchasing inks. You may also want to read things at PenTrace.net. There's a wealth of knowledge there. And check out Richardspens.com He has articles that may be of interest.
Hope this helps.
If you decide to take the pen apart, say so and I'd be happy to give you some hints there. Alternatively, Deb McKinney does a great job of pen restoration and she smooths and shapes nibs artistically. I'm thinking about sending all my kit nibs to her to reshaping before I install them.