You may:

-Use this mod, obviously

-Modpack this mod

-Reupload this mod as is with permission

-Modify (E.g. adding new structures) this mod and or upload it without permission necessary

-Port or backport this mod--as is or modified--to other versions without permission necessary

You may not:

-Claim this mod as your own

-Reupload this mod as is without permission

-Upload this mod--as is or modified--for real currency and currency that can only be or is primarily (E.g. freemium currency that can be obtained through gameplay, but is far faster to get by simply paying) purchased.  My mods are free, and always will be.

For anything not covered:

Use common sense!  If it seems wrong, don't do it.  If it seems gray, ask first.  If it's generally in the bounds of what you can do with the mod, then 9 times out of 10, it's fine!