Don't forget that the main way to hire workers is by spending some cash to hire a worker using the button at the bottom of the screen. The button also shows the current level of workers you can hire and the cost for one.

As you hire more workers, their starting level increases, but so does the cost, which rises steeply. Choosing when to spend cash on workers versus other improvements like the workbench or the apartments is part of your strategy.

Every time you find a brick wall, the hiring price will be reduced. Don't forget to check the cards section to find a permanent discount for your workers, too! 

The crane increases your workforce! The timer above the crane operator indicates the time remaining to get a new worker. The crane also periodically delivers mystery boxes, which can contain resources, including new workers! These mystery boxes appear in front of the workbench from time to time. 

Merging is another key mechanic: combine two workers of the same level to create one of the next higher level. Just like in the pattern, you know, you don’t add their levels numerically — for example, two level 2 workers merge into one level 3 worker, not level 4.

Higher-level workers use better tools and complete tasks much faster than lower-level ones.

Also, keep in mind that there is a limit to how many workers you can have active at once. You can see this limit at the top right of the screen. If you reach the limit before hiring a new worker from a mystery box, you won’t be able to get that worker until you merge or make room by managing your workforce.