Well I heard the coolermaster 212 comes with thermal paste itself, is the one that comes with it electrically conductive?
TIM shouldn't be conductive...some is 'mildly' like some AS products, but you are only using a tiny amount anyway...and it should ONLY be applied to your IHS and cooler. If you put on that much that it oozes out the sides and onto your board...you are using about 100x too much.
Also is thermal paste really required? Can I just slap the cooler on without it? This is my first build and I dont want my computer to explode or anything
Not 'required' but very strongly recommended. The IHS and heatsink are not perfectly flat or exact matches for the other (unless you lapped both surfaces...voiding the warranties of both). Thermal paste (TIM...thermal interface material) fills in any microscopic voids between the 2 surfaces and allows more efficient heat transfer...air does not transfer heat effectively.