Right because only MTG players ever use abbreviations. But even as a MTG player this dude used way too many abbreviations then neccessary, particularly som and bop. I only figured out som from the other cards mentioned and bop I had to look up>>62710738
I can shed some light on this
Som standard means when scars of mirrodin was legal to play in standard format. MonoG is short for mono green which means usually means a deck of big smashy creatures, the ramp means being able to build Mana really fast to play those big things sooner. UW is blue white which usually means a lot of control cards to shut down the opponent.
The first two things were unneeded info, just means both dudes kept the opening hands and didn't Mulligan. Unless you mention 'they mulliganed' one will auto assume they kept hand
He had no reason to mention 'taps for g' since he already mentioned the forest, means he gained one green Mana to cast a spell. BoP is birds of paradise, a turn one creature that taps for more Mana, again, letting big things come out sooner.
T0 means turn zero, means UW guy still didn't take his first turn. Mental mistep is a counter spell that can be played with 1 blue mana or 2 life and can only cancel out one cost spells like the birds.
Summoners trap I can't remember what it does, but trap spells in MTG have conditions where they can be played cheap or free if the condition is met. Assuming the condition was if your creature got countered and cost is 0 to be able to put another creature on the battlefield
Ulamog, is a big nasty bruiser. Real big. Equivalent to a 9 Mana creature in hearthstone, a fully evolved Pokemon, etc. Dropping one on turn one means the opponent has no hope of winning.
Hope that helps clear things up.