The game is free to play RuneScape gold I highly recommend you guys to start playing on the PC version just to get use to it. You can experience the game to a good amount just on free to play alone. There's over 30 quests you can do for free to play.
Hundreds more when you become a member and there's quite a few skills such as mining, smithing, woodcutting, fishing, cooking, range, magic, melee, etc that you can do. The rest of the skills are limited to members only but you don't need those to enjoy it at the start.
The controls are very simple so you should have no problem transitioning to mobile besides for harder tasks such as bosses. It's basically just a point and click kind of game so you really only need your mouse.
There are guides for pretty much everything such as best training OSRS Gold spots for certain skills and guides for quests. The subreddit is very active so go check that out as well.People would be happy to know that you can buy membership with in game.