Blocks in our system are executed sequentially, in the order they are arranged. To illustrate, if you want an object to spin and then catch fire, you would snap the blocks together as follows:

By default, each block activates only after the previous one has completed its action. This means the object will first complete its spin before catching fire. However, if you want these actions to occur simultaneously, you can adjust the settings. Simply uncheck “Wait for completion” in the expanded view of your block.

In that way your object will catch on fire while “Spin” is being executed.