Hi,
It depends.
First, by default when you install a new HikaShop 3.2.2 it isn't the default behavior. By default, it works like you said you want it to work.
So you must have changed something (settings, third party cart module, etc).
I would recommend to check the "add to cart legacy" setting of the hikashop configuration.
If that option is on, then you're using the old add to cart system, and below it, you'll find an option "When a product is added to the cart" where you can configure the behavior.
If that option is off, then you're using the new add to cart system and in that case, you'll only be redirected to the checkout if you have the HikaShop cart notify plugin deactivated in the Joomla plugins manager and that you have the HikaShop cart module deactivated in the Joomla modules manager.