1. how can i reconnect disconnected poöygons?

2. how can i add connections between disconnected polygons?

3. when i make new idles, do i only have to make the idle state?

1. Weld them back together
2. Too many answers, but you could bridge them, weld them, connect them using the Polygon tool....
3. I don't understand what you're saying, if you mean you created a new idle animation then whether or not you need more animations is up to you

A little more info and maybe some pics of what you're trying to do would help us help you even better.

1. with the weld poly tool? ok thanks

2. ive tried to connect them with the add edge tool, but it wont work, how can i bridge them?

3. i want to make new idleanimations for lightsabers

and 4. can i export anims, i made with the modtool, to xsi 5?

2. The Add Edge tool just adds edges to existing polygons, you can't draw an edge in space, use curves to do that.
Here's a demonstration video showing 3 different ways to connect polygons:
Connecting polygons
The second method shown is by using the weld function of the Tweak Component tool, press M on your keyboard to activate the Tweak Component tool.

4. I don't see any reason why you can't, try it and see.

sorry for the late reply
thank you, i got everything as i wanted it