You can't. Fractal settings aren't saved with the entity. Technically, there is no such entity as a fractal line, it is a regular straight path with a lot of off-axis nodes. The settings are only used within the command that draws that path, once it is done, the parameters are forgotten.

Best way to experiment is to set the fractal strength and depth in the fractalize dialog (Just Escape out when it asks you to select a line to fractalize afterwards), then draw a line with the fractal path command and repeat till you are happy. You can of course use the arrow keys and then try to approximate the amount when going back tot he box for the next test. I am not sure how much the strength increases/decreases, but the dept is increased/decreased by one for each key press.

If they are partially overlapping, the simplest way to merge them is with the TRACED command. This will create a new poly, so delete the other two afterwards, and change properties on the new one if required.

The link below shows how to use TRACED. The example uses a single bitmap image, but it works just as well on a set of polys.

Check this FAQ entry. It contains a pair of video links in addition to the text.

Normally, you shouldn't need to change anything, as the tools and sheets should be set up to make everything just work unless you are trying some more advanced techniques.

Looking at your screenshot, I notice the Sheet setting for the tool is blank. The default setting for that particular tool should be LAKES*.

With that setting blank, it means that CC3+ will NOT attempt to put it on the correct sheet automatically, meaning you'll have to take care of things manually. Basically, that means you need to set the sheet to LAKES manually before starting drawing. I see it is set to LAKES currently in your screenshot, so assuming that your landmass is indeed on the LAND sheet, it should work right now, but if you change the currently set sheet, it will go to that one instead.

If it doesn't, confirm that your landmass is indeed on the LAND sheet, as rearranging sheets won't do a thing if entities aren't on the appropriate sheets.

Basically, use Info -> List on your landmass to check it is on the LAND sheet, on the lake to check that it is on the LAKES sheet, and that the sheet ordering is with LAND appearing higher up in the list than LAKES.

And to add what Loopysue said, make sure that your rivers and lakes really are on those sheets. They won't automatically go there even if you have sheets by those names, where they go is determined by the setting in the drawing tool.

You can always check witch sheet an entity is on by using the the List command from the Info menu, or simply hiding all other sheets than the one you wish to inspect.