How to create a portfolio read HERE.
Go to "Portfolio".
Scroll the page down to "My portfolios".
Select a portfolio for rebalancing. Click on "REBALANCE".
Add or remove cryptocurrencies in portfolio, having selected necessary cryptocurrencies from the list. Make changes in a table and click "REBALANCE".
In the pop-up window the table will appear, which shows how much and which cryptocurrency you need to sell / buy. Click "Confirm" to make changes to the portfolio, or Cross icon to cancel changes and continue the rebalancing.
If the portfolio has been successfully rebalanced, then you will: "Rebalanced successfully" in the upper part.
The portfolio rebalancing is complete.