If there is a stock split, your respective Decentralized Assets (dAssets) are going to reflect that change. There is nothing you need to do on your side.
The most important thing you need to be aware of is that dAssets cannot be traded 2 hours before the stock split and 2 hours after (4 hours in total). This timeline may be shortened in the future. Everything else will be handled automagically.
If, for example, AMZN had a stock split of 1:20, your dAZMN tokens will reflect that change and you will have 20 dAZMN tokens for every 1 dAZMN token that you held previously. The price is likely to follow that change.
Again, there is nothing you have to do as a user. Just be aware of the 24-hour trading lock for dAssets that are going through a split. Thank you!