i have finished my lessons, but lesson 461, 462, 473, 474 still locked, how Can I open this lesson?

April 28, 2019
#$%@4-
![]()
#$%@4-
.
11403
![]() you can open these lessons by using your coins
|
||||
![]()
#$%@4-
.
2
![]() how can i use my coin?
|