Introduction:

Use the second conditional in circumstances of condition and for situations that are not necessarily real or they are imaginary.
Compare:
If I see john I will say hello.
If I were to see John I would say hello.

Structure:

If clause past simple (remember to exceptionally use the auxiliary ‘were’ in all voices)
(If I / you / he / she / it / we / they were you ….)
Resolution clause use would (in modal form) + verb
The second conditional can use were with the verb to be.

Examples:

If I were you I would go.
If I weren't there, he wouldn't have said so.
Were I there would you have come?
Were they not there would you not have come?