Kohler Wellworth problem - low water in bowl

I installed a new Kohler wellworth toilet in my house and everything seems to be ok but the bowl only fills up a tiny amount after flushing. I have a few of these in my house and the water amount in the newly installed one is much less than the others.

I read the installation manual but did not see any way to adjust for this.

How can I adjust this to get it to the correct level?

Thanks!

There may be a fill tube that needs to be directed to the overflow tube.

Check to see if the other toilets in the house have a black tube going from the fill valve to the overflow tube.

Thanks Terry!

I feel so silly. I spent an hour trying to figure it out and I was focusing on the flapper. My tunnel vision prevented me from seeing that the tube was not connected.