This game is not new. Initially found online, probably waygook, but can't find the original posting. While the idea is not new, the documents included are what i created from what i read.
2 different documents. one is if and then (conditionals) The other one is "When someone _____, ______.

Cut sentences out. Give each student one. Give some students 2 depending on class size. My middle school is 28-32 students each class.
I time them twice, using online-stopwatch.com. 1st time is more like practice. 2nd time. collect the cards. pass them out again, and repeat. They usually go much faster and its usually fun for everyone.

I'd say design the game how you see fit. My students are really low level, so i use stopwatch and count up rather than a timer to count down.  I do a quick demonstration of conditionals. If I say "go," raise your hands. and get everyone to raise there hands after go. explain that this is an example and that all the cards look similar to this.

After handing the slips of paper, I give them time to read and ask questions if they dont understand their role. The first time is really slow and i read out the next slip of paper if the whole process stalls, which, on the first round, usually happens given my 28+ students. The first week i tried this, I had a tournament within the 2nd and 3rd grades, showing the class which times they had to beat if they wanted to be first. the first run on the if/then beat the clock yielded from 2-4 minutes. 2nd times are much quicker. You can take the best time, I took an average. whatever works.