These cames are HARD! You can find walkthroughs for all of them easily. Myst IV even has a hint system built in. But don't use them too quickly. Listen to all the sounds the items in the games make carefully, note their shapes and colours, and try to see the connections between them, and between the different items in the games. I remember in Myst I there was a button somewhere that I couldn't see even after I read a walkthrough, so I had to click at a certain place 'blind' to reveal a passage. And in myst IV (by far the best of the series in my opinion) there was one puzzle I didn't understand even after referring to all the hints about it.
I loved all the Myst games except
Myst V (warning: spoilers in the linked thread).
