[header] How to make tapa [title] Slice the beef into thin, pinky-width slices. [step] You want to cut against the grain. To cut against the grain, look at the long horizontal strands that run through the steak and cut perpendicular to them. 
[substeps] Don't be afraid to leave a little fat on the beef, it will help it cook later. [title] Mix the vinegar, soy sauce, pepper, and garlic in a bowl.