Since I like avocado, I just scraped it with a spoon and fed it to DD. Then I ate the left over.
You can puree it.
you can cut it into cubes. (Most babies will just mush them until they get better coordination. It's messy but teaches them needed skills.)
I would not add salt. Babies don't need salt for food to taste good.
**I think it is a personal choice of when to give solids. I know that most people no longer start solids till the child is 6 months BUT that is a recent thing. My DS is 9 and the recommendations back then was 4 month. Needless to say, everyone ...even the daycare thought I was nuts for waiting till 4 months in those days. Many people start "solids" earlier by giving a little rice cereal at night etc. DH was started on solids at less than 2 weeks old!(Cereal in his bottle and spoon fed mashed potatoes). I would see how your child is responding to you eating. IF your child shows and interest, I see no harm in giving them a bite or two. You should not expect them to eat large amounts when they first start solids. Just a few bites.