Portfolios are a group of stocks. A Portfolio can contain many stocks. A stock can be part of many Portfolios. Some people use Portfolio to regroup by brokerage accounts, some people use them to regroup by commodities, by market, there are no rules.
To change the name of a portfolio, press the Edit button at the bottom of the screen. Note AutoRefresh cannot be modified.
To add or remove one or several stocks from a portfolio, select them and simply drag them to the content list, reverse the operation to remove.