help build my team

Okay...I'll answer you.
Buster crit team: Shishou (crit star gen use CEs like Be elegant), Nightingale (buster support with her third skill), and Rama (against lancers equipp him with starting NP CE best with summer time mistress), Kiyo (Against archers) or Drake (Against casters), Sieg (against dragons and only against dragons) and Martha (general against enemies I didn't mention).
For buster teams and if you want being defensive running a mash, Carmilla/Rama/Kiyo/Martha/Drake and Nightingale.
For arts you could only farm. I don't suggest Edison or Marie so raise Helena as your AOE caster (Put a Kaliedoscope or starting NP CE or maybe an arts performance enhancement CE) run tamamo and mash and there you have it. You should borrow any other arts servant like Lancelot saber and Artoria Archer if you want something better and run them with Mash and Tamamo.
That the things you could run.

The first servant you should heavily invest in is tamamo. You have decent not awful buster crit pieces like Tama and kiyo and star gens like shishou and carmilla but nothing too exciting.

Tamamo on the other hand is currently quite likely the second best support in the game among casters. Having her max ascended (if you don't yet) alone opens up all arts teams (you will have to use someone else's arts dps for now).

Given how few pieces you have, my suggestion to you would be level and develop shishou first and foremost, as she is super easy to max ascend being a welfare servant and not requiring large amounts of ascension material. Then put as much as you can into getting Tamamo up. For the dps you have, you can spread it evenly but kiyo is the best in the list you provided at pure dps that might be easiest to raise. Drake is your best dps servant (even though her primary role is as a hybrid) but max ascending her will take longer and more resources so start with kiyo then her. Just focus on developing pieces as ultimately you will acquire more over the course of summoning more.

I've been playing the game for about 5-6 months and I still haven't focussed on team building yet but rather on collecting pieces to make teams and have cleared to current content anyway (including Camelot). Still have 3 months to prepare the pieces I have (and I have quite a few now just from 5 months of play) for Babylonia and make teams to trivialize it so keep collecting pieces and materials. It's a long game and you have time.

TLDR: Don't worry about teams as even upto Camelot, you can get by with max ascension and class advantage. Make sure you have as many max ascended pieces as you can. Welfare servants like shishou are far easier to max ascend due to their lack of need of tons of ascension material.

Invest in your 5*'s. They will most of the time outperform many lesser * servants. Drake will be super good because of her NP and how fast she gets it with her skills. And when paired with Tamamo, NP spam can be your thing. Your arts servants can also complement other support servants so do look out for that too.