How to increase number of characters or words in excerpts?

Hi

I have the Fineliner Theme and after 2 days no reply from support…

I ‘simply’ want to know how to increase the number of characters/words on the ‘excerpts’ from posts that get displayed for example from the Blog on Page 1 - there doesn’t appear to be an option for that?

Can anyone help?

I have tried adding code to the functions.php but it didn’t work.