Note that the slats which all run straight vertically down the front can be easily placed using the Move tool in its “array” mode. Using @DaveR’s drawing, the first six slats would be placed manually one-by-one. The sixth one is apparently the first slat to be straight vertical.
With that sixth slat placed, use the Move tool to create a copy of it (which will be the seventh overall slat); position that seventh slat straight below the sixth, at the desired distance from the sixth (you can type in a distance to make it exact). Now with the Move tool still active and without having done any other moves, you can type “x10” or “x50” to cause SketchUp to replicate 10 or 50 etc. slats, instead of just the one single slat (the seventh) that you had manually positioned.
You can experiment to get the desired number of additional vertical slats. If 50 is to0 many, type “x45” to see if that fits better. If 45 is too few, type “x48” to change the number of them again. You can continue to revise the number of objects in the “array” until you leave the Move tool or you manually position something else.
By the way, there is an alternative form of the Move-copy-array tool which can be helpful in other circumstances. You can type “/” instead of “x”, for example “/10” or “/50”, to cause SketchUp to distribute lots of objects BETWEEN the starting point of the object you copied and the position of the copy. For example, if you wanted 25 slats evenly distributed down the front of the object, you could use Move to copy the sixth slat all the way down to the bottom end of the object. Then type “/25” to cause SketchUp to fill in a total of 25 slats (instead of just the one you manually placed at the bottom). You can revise the count after the fact: type “/24” or “/35” etc. to tweak it.