Change vaults

I accidentally wrote a note in the help file. Now, I cannot get my own vault to be recognized by Obsidian.

Things I have tried

I tried to down load another obsidian. At first it did not ask to open a folder. Later by accident I discovered that it did. So, I did get into my own vault. But, This is a messy work around. I don’t even understand why this happened. GROAN

What I’m trying to do

To change vaults you need to open the vault picker from the ribbon (on your left, a tiny vault-looking icon).

I see it. Thank you.