they're trying to find a job according to their ideals.
they're trying to find a job agreeing with their ideals.
（according to 和agree with 都有“与…相符”的意思）
they're trying to find an ideal job.
belong to 是个动词词组,不能说was belong to
开头they are try to 也不对,be动词直接与动词连用.