Everything seems to be working well except I cannot work out how to save the game. I am sure there is a way. Please tell me. Thank you

It should just autosave as you progress. When you want to exit the game, you put your mouse down near the bottom of the game screen, and some icons should appear, the exit being on the far right.

So have you completed the basic journey/checked the cloth?

You will always start at the beginning (in the desert) until you find all the journey cloths and enter the tree.

After you gain access to Relto (island in the sky) you will ALWAYS start there. Each age has journey cloths that act as "save points". When you select a book from your bookshelf you can start at the beginning of each age or from the journey cloth you left off on.