Practice, practice and practice. Find a sand patch and cross it several times. Once you get used to the sand feeling, it will be easier.
Enter the sand patch at a steady pace and try to keep the same pace. Don't worry if the bike tails a little. It should recover on its own unless you panic brake or hit the gas.
Basically, the strom is a heavy bike, and will not do great on deep sand. Maybe upgrading to more off-road oriented tires would help, but your best bet is to practice and understand how the bike handles on that situation.
And, then again, practice and practice one more time. You may watch videos and read recommendations, but practice makes perfect.
I is poor doge... I no know bikes!