How do i write music like real screamo bands such as pg. 99, city of caterpillar, funeral diner, and pianos become the teeth. like how do i write the slow buildups and what chords are commonplace and how to they create that really intense feeling in their songs? and how do i write lyrics like theirs, theirs lyrics to me just give me like a mood or feeling that my own dont.
Strong question, I'll do my best to offer what advice I can because I used to be in a screamo band.

Slow build ups is just about layers really, start with like a minimal riff then just add more to it - embellishments, chords, feedback, volume swells etc - but build them real, real slow for tension, dropping elements out for portions of the build can be interesting. This really works best with two guitarists (it can be useful to write with a looper if you've got one) but make sure not to neglect bass and drums either - never underestimate how much you can do with the bass particular for adding some weight to the sound, move away from just roots if you're not in a heavy bit. Then when the time's right drop it in into thrashy chord type stuff, fast changes and lots of high notes.

Chord wise I think it really is anything goes, I used to just mess around until I had the sound I wanted without thinking about shapes at all, there a quite a few jazz type chords knocking around I think (make of that what you will, my theory is very substandard anyway) but also power chords, bar chords, completely atonal chords depending on who your listening too. Chords used is often more influenced by tuning than anything else, there are just some things you can't play in standard, but also things you can't play in dropped/open tunings too (both of which get used).

There's nothing specific that I'd say is used to create the intense feeling, it's just something that happens when you have a lot of emotional involvement in the songs you're writing because it shapes how you want them to sound.

Lyrics wise just write about something very close to you, a lot of lyrics take on a stream of consciousness flow (particularly city of caterpillar and other slow build stuff) or feature a shit load of abstraction/metaphor (CTTS) or are just incredibly honest (PBTT). Listen to more screamo and read the lyrics and practice, that's the only way to get better.

Most of what I've said is just my poor attempt to classify the writing process in a way that might make some technical sense but take it with a pinch of salt because tbh when I was writing this kinda stuff I didn't give a shit about what I was supposed to be doing, I was just felt a compulsive urge to make music about things, and I think that's what a lot of bands are doing. Just do what you feel is right.

These days I just make noise.
thanks thats actually pretty helpful but did you ever play with a keyboardist? if so do you have any tips for writing keyboard parts, because we have one guitar, bass, keyboard, and vocals (still trying to find a drummer)
We didn't ever use keyboards, so I can't help too much, maybe the Gear for Post-Rock thread would be the place to ask? Can't remember if there's a post-rock bands&artists thread.

Make sure you spend enough time setting up the sound presets, that has a huge influence on what you'll write on the keyboard (ambient swells are totally different to piano sounds for example).

Depending on what keyboard/synths your using you might be able to use one as a drum machine if you can't find a drummer, though you might end up sounding pretty industrial (dunno if that's your kinda thing). I once saw a one man band pull off powerviolence, so it can be done.
any tips for writing spoken wordslike a lot of bands do such as the kodan armada, old gray, and being as an ocean? theyre spoken words are really moving and i get that its just poetry(but really all music is) but i still cant write good spoken words.
It all depends on who you're listening to for the most part. If it's someone like Orchird or Pg. 99, lose your ****ing shit with power chords. If it's someone like Merchant Ships or We Were Skeletons, try to include a lot of odd timed, hammered on/pulled off riffs and tapping. With influences like Funeral Diner and Pianos, there needs to be a more ethereal, post-rock sound. So on and so forth. The only ground rule for screamo is try to write as personally as possible. Write shit that brings you to tears, no matter how inane it might sound in your head.
Also, if you're in a screamo band, hit me up because so am I and networking is the shit.