You can poke holes in the terannium with a drill, pen, knife or something sharp, if you have already planted it, then be very careful not to waterlog it, which could rot the roots. Keep it just wet not to much.

Terrariums and carnivorous plants aren't generally a good idea. They may appeal to the aesthetic sens but tend to require more maintenance and lend themselves to mold issues.

Here are alternatives that can be done aesthetically:

{{gwi:550326}} Rack at window

{{gwi:550240}}large tray under artificial lighting

{{gwi:551219}}Window sill

do they grow very well on method you use?

They get more intense redness if kept outside, but many of those sundews flowered on window sills and under lights.

I dont have a window sill that gets direct sunlight though. But now I know terrariums are bad idea i am going to try to use the open tray method the only reason i bought a terrarium is b/c i read on a website that you have to protect sundews from air-condition. I did start the tray method today though but since i have no window sill that gets direct sunlight I was thinking i will put the plant outside on my deck in the morning b/c that is the only place where there is direct sunlight. And i will bring the plant inside when it gets dark. Is this a bad idea b/c i am not sure if the plant will go in shock b/c of the teperture will change if i do it. Also i was wondering my plant looks as small as your plants do so how do you feed yours b/c when i feed my plant it does not eat or even try to eat it.
the plant does have a little dew on it but the insects do not stick.

Normally, it isn't a good idea to be moving plants around. I would do so only if there is a freeze or an intense storm. I haven't found AC to be a problem because the open tray method provides 'local humidity' through evaporation. You can also buy freezed dried bloodwormsa (fish food)and sprinkle a little on the leaves. Dew is a function of adequate lighting, along with being acclimated and reasonably happy. A fluorescent light works well enough for most plants.

Ok so I will buy a fluorescent light for my plant. And also for the freezed dried blood worm are they small? And do they sell them at petco? Also do you know what stores sell fluorescent lights?

Petco should have all you need in terms of fishfood and plant lighting. A mom & pop petshop / tropical fish store is probably better for advice, though. Pulverize the food with your fingers.

Terrariums are generally not a good idea, however I grow a ton of Nepenthes in them and they do great. I have a couple rare ones too. For Sundews, VFTs, and Sarracenias however, they aren't usually necessary since they don't really require high humidity. If you must go with a terrarium, keep the plant in a pot and elevated above the bottom of the tank (especially if leftover water has pooled there). Also keep the cover open or off-center a little bit to allow for ventilation.

For fluorescent lights, just pick up some cheap shoplights at Home Depot. They have a 2 T12 bulb 4ft. fixture for 9$ (cheap Lithuania Lighting fixture). Get 2 bulbs of 6500K daylight bulbs and you're good to go (about 4$). You can always double the fixtures if you want more plants and better growth.