You cannot (at least, not in a standard/supported/known working way); a Worklight project contains Worklight applications but cannot contain other Worklight projects. Worklight projects are always contained directly within an Eclipse workspace (unless working with the CLI tools).
Based upon your clarifying comment, it seems that your containing "(general) project" is just another directory that contains a wl
directory - not a real Eclipse project - that in turn contains your Worklight project. It seems you are creating the whole thing using the CLI tools.
In order to work with this project within Eclipse, you'll need to create a new Eclipse workspace elsewhere (the Eclipse workspace itself isn't particularly important and doesn't necessarily need to saved in source control). You can then use File->Import->Existing Projects into Workspace to import the Worklight project from the wl
directory. You can either "Copy projects into workspace" (in which case you will end up with two copies), or leave that unticked, in which case your Eclipse workspace directory will just contain a reference to the original directory (I suspect you want the latter).
As a word of advice, generally you should try not to work with both Eclipse and the CLI tools at the same time. Although it may work, you will get conflicts with (for example) the embedded test server, and long term, you'll just cause confusion.