Question

How would I use the word "Salvation" as a noun in a simple sentence?
My first sentence was He gave salvation, but he is the noun in that sentence. My second sentence was Salvation was given.

Answer 1

You are mixing up noun and subject. In your first sentence, He is a pronoun and the subject. Salvation is a noun and the direct object of the verb gave.

If you need to use Salvation as the subject, your sentence is o.k.

You could also say,
Salvation is a key tenet of Christianity.
or
Salvation of the world's forests is important for the environment.