Alright, that's the Ninja Special Ed response. Lemme go a bit more in depth, though the comparison is on point.
Blast, or Explosion Release, is a KG formed of Lightning and Earth chakra. It creates explosive force when Taijutsu attacks are created. This allows Gari and someone from Sasuke Shinden the ability to release explosions when delivering Taijutsu blows, making it a very dangerous element in close range. With the user generally immune to the force as it blasts outwards, you're able to chain together several explosive blows in quick succession.
The two forms of Blast are the normal form, the one described above, and explosive clay. The latter is very unique and in the series was the result of a hidden Kinjutsu stolen by Deidara to allow the user the ability to knead chakra into substances. With this, he infuses his Blast chakra into items to create ranged explosions instead of the normal short range variant. This is the main difference between the two forms: One is always ranged, the other is always CQC.
As for S/W, Keep this in mind:
Weak to: Lightning and Water. Lightning can defuse the detonation process while Water itself can be used to either contain it or counter it. In the case of the specific Clay Variation of Blast Release, Fire can be used, also, to either Melt the Clay (in the weaker applications) or "cook" it, in the same way as one does with RL Clay, turning it to rock.
Strong to: Earth and Wind. Earth can't contain the explosions and is weak against them while Wind is ineffective to control or contain them.
That said, if you dont have any questions, we can move to techniques. Pro tip: I require at least 2 questions before we go on to make sure you following me so far.