If you’re new to it firstly accept that it’s going to take time for you to learn more self control and how to edge without cumming, so don’t beat yourself up about it, just have fun.
Secondly the most obvious answer is wear more layers for your grinding, two pairs of panties, or panties and leggings or anything up to a pair of jeans. Every layer will make it harder and last longer.
On top of that, add some quotas, e.g. only 100 grinds before you are only allowed to play with your breasts for a minute to cool down. It can be very hot having to count, then stop, and you should explore with numbers till you find one that keeps you really horny but just isn’t enough to make you cum.
Also set up some ‘punishments’ if you do cum. For example you’d not be allowed to touch the rest of the day or you have to stuff your pussy with your panties or give yourself 20 hard pussy smacks.
Try those out and hopefully some or all of them will help!
Good little grinder!