All Portfolio option is available in admin panel >> Portfolio >> All Portfolio. 
If you will add your own Portfolio(s) in your theme , then Portfolio list will be show here.
From on hover on any portfolio you will get below given option(s)
1. Edit :If you will hover on any portfolio in list, you will get edit option edit, by clicking on that you will be on edit Portfolio, from there you can edit Portfolio info like featured image, Portfolio Link, Portfolio title / name, Description etc...
2. Quick Edit : By Quick edit you can edit some most information(s) like Portfolio Title , Description , Status etc...
3. View : View Option is for view your Portfolio. If you want to see portfolio with your matter like Title , Description etc... you can use this option.
4. Trash : Trash option is use for delete portfolio(s).
Bulk Actions : [3.2] You have all portfolio(s) list in below given image , if you want to take bulk action on one or more then one portfolio(s) , you can mark[3.1] and select Your bulk action like delete[3.2] etc...
** If you want to add a new Portfolio you can click on Add Portfolio option.