I hope Red doesnt mind me chucking in a few things here.
If you want to change the value for your snap to grid, so the jump is more or less, you can change it in the preference window. To open it, go to the file bar up the top and go file -> Preferences. This should open up the following window:
The two boxes circled are the one for snap to grid and snap to rotation. The defaults are 64 (grid) and 45 (rotation), but I personally prefer using 32 or 16 for my grid (16 is sort of a must for fort pieces, but otherwise 32 is normally good enough) and 45 degree turns. If you are just building a layout, then a rotation snap to of 90 is just fine and can save a little bit of time.
Suggested grid value guidelines. Us numbers that are multiple of 2, eg:
2, 4, 8, 16, 32, 64, 128 ...
As most layout pieces are built for these numbers. If something isn't fitting together right,just drop down a value and try again, i have had to go as low as 4 at times to get things to fit with snap to grid.
Suggested rotation value guidelines. Remember degrees in school? You want parts of 90 to make most of your stuff. eg:
15, 45, 90, 180 ...
Most of the time you will only ever need 45, if you want something else you might as well just do it by hand or by a value you. I have never had to change my rotation value.
One final tip: The fort doors are poorly aligned, whenever you place one, you will then have to move it up 2 on the z-axis to make it fix the frame.