My Lands: Black Gem Hunting

New to the game and I need to know how to add workers, can some one help? I also need to know how to add allies or accept allies?

First study diplomacy,
construct a Diplomatic corps and enter it
invite someone

To add more available workers? Or to add more workers towards something that is currently building?

For the first, build more cottages or upgrade them.
For the latter, go into the constructing building and there is a slider bar you can move to add or subtract the amount of people currently helping build/upgrade something.