the people give you hints to find gym leaders.
go into the gym
In the gym!
i only know two:Chuck and Jasmine go to google to find the other gym leaders
There in the gym in mossdeep city by the way the gym leader are actually gym leaders.
On the last gym leaders map
One of the gym leaders give it to you
just battle the gym leaders just battle the gym leaders just battle the gym leaders
you find rock climb from one of the gym leaders. easy as that.
you must defeat 7 gym leaders
various gym leaders will be in various cities. you can fight them in any order, depending on whether or not you need special moves to get to them or whatever. you just have to travel around and you will find them.
You have to search Johto and Kanto and find all the gym leaders out side of there gyms and and then talk to them and they will eventually give you their numbers
To find blue defeat all of the gym leaders and then go to cinnabar island blue will be there and will accept your challenge if you have defeated all of the gym leaders. Then go to viridian city gym and get through all of the trainers. After this you can also battle red.