You cannot on Honda's CVT transmission. There is no transmission dipstick.
There is a fill level plug underneath that lets out any overfill.
I do the CVT fluid swap every 25,000 miles (30,000 KM) for long life - the lubricant in the fluid dose wear out and needs replenishment.
Never ever flush a Honda transmission - it destroyer the permanent filter. The Honda CVT fluid is not that expensive and will extend the life of the CVT transmission.
I takes about 4 quarts of CVT fluid to do the change and 2 crush washers to replace the ones that were in the drain and check level bolts. After you put the 4 quarts in you open the check level bolt and allow the excess fluid to leak out.