Addition on the Abacus

The Abacus is a medieval age calculating tool. Shown are several positions of beads on the Abacus used to depict different numbers. There are two frames top and bottom with beads. The center of the horizontal axis can be considered as the Units position. The four beads in the bottom frame in the units place are equal to 1 each whereas the value of the bead in the top bead is equal to 5. Any 3 digit number (for example) can be written as 100 X + 10 Y + Z where X,Y and Z are numbers between 0 and 9. In the picture below positions of the beads for 3 different numbers the first one 0 , the second one 2 and the third one 7 have been shown. Similarly simple decimal addition using a sequence of operations has been shown on the Abacus in the next picture below. Question : What is the correct sequence of movement of the beads on the Abacus for adding 7 to 18.
(18 + 7). Assume that the Abacus is set to 18 initially.