As the addon description for "First Landing/Base" says, this is a replacement for the default base, and you will need at least some of the other First Landing addons to get a valid world. Just deactivate everything (using the handy "clear all" link at the top of the generate page) and select every addon with a First Landing prefix.
Once you get that working you can experiment with adding default addons (some are not First Landing compatible) and tweaking the settings with the configuration variable editor.
how do I know if it is working? and after I turn on the rubble web thing, do I just generate raws then run the regular launcher?
Generate the raws like you would normally with Rubble, just with the First Landing addons instead of the default ones. Once the raws generate (without errors, Rubble will report how things went (and if you get any errors I want to know about them)) simply start DF like normal and generate a new world.
If things do not work then check to make sure you have no non-First Landing addons active, then try again. If it still won't work than you may have a bug, ask here and I will help you. Some non-First Landing addons are known to work fine with First Landing, but I have not had time to test them all, so if you want to use some of them try adding one at a time so you can easily tell which one's do not work (and let me know if you find an incompatible addon so I can add it to the incompatibilities list).