@Dennis1948
How did the months up to July get there in the first place? You're asking a question that presumes knowledge that only you have. The rest of us can guess, but....
So whatever method you used to create the chart in the first place, use that same method to extend it to July. You may be able to do something like right-clicking on the side of the chart that displays the month, and then extend the range.
One of the neat things about Excel is that there often are several ways to accomplish a given task, and it's always possible to play around with (in this case) the existing chart until something clicks. I would encourage you to do just that; save a copy under a temporary name in case you have to go back to the starting point, but then give yourself permission to "play." It's one of the best ways to learn.
