In a simple ACTIVE PREDICATIVE sentence:
Subject + Vb --> Yo trabajo = I work
If you want to add some information, add "complementos del verbo": there are a lot and vary depending on what you want to say: CD,CC,CI... F.e:
Sbjct + Vb + CCL --> Yo trabajo en casa = I work at home
Sbjct + Vb + CCCompañía --> Yo trabajo con mis amigos = I work with friends
But there's a kind of sentence which is the ACTIVE COPULATIVE one, and says something about the subject:
Sbjct + Copulative Verb(ser,estar,parecer) + Attribute(adjective or noun)
Yo soy profesora = I'm a teacher
Yo soy guapa = I'm pretty
Unlike the previous ones, you just CAN'T remove the thing after the verb,in fact, IT HAS TO BE ALWAYS THERE, else, the sentence wouldn't make any sense(in spanish at least, in english it could be fine if answering a question like "are you okay with this" --> "Yes, I am"):
Yo soy = I'm ??
But, sometimes, even if there is a copulative verb, the sentence can be PREDICATIVE:
Subject + Verb + adverb/CC...
Estoy en la estación de buses = I'm at the bus station
As you can see, it depends on the context ;)
What about passive sentences?
Sujeto paciente* + (Auxiliar verb+Participle) + Complemento agente*
*Complemento agente is the thing/person who actually does the action, and the Sujeto paciente* just gets affected by it.
Yo fui curada por el médico = I was healed by the doctor
Hope this helps, these are the basics, IMO ^^
