How do I get more builders?

You need to get to VIP level 6 and get the second builder queue item. you can see if you have it by going to the Items link and selecting Others, it is a scroll with a red seal on it. Super useful to have!

You start the game with one builder, which is annoying, but at the start of the game you are given a perk to open a second builder queue for two days, you should activate it right away and utilise it as best you can to grow your City as much as possible before your initial shield expires and you can be attacked.

At VIP level 6 you permanently open the second builder queue.

During the game you may get the 2nd builder queue perk given to you again.