Crafting a lead in minecraft pc - what's the trick?

wandering trader's llamas are on leads. kill the llamas (or the trader) and the leads drop. bit grim, but it's two free leads whenever one wanders past your base.

4 string and 1 slimeball. String top left, top middle, middle left and bottom right, slimeball in the very centre. Makes 2. The slimeball is the hard bit. Slimes only spawn in slime chunks deep underground or in swamps at night, so early on it's mostly luck. Wandering traders sometimes sell leads outright, worth checking before you go hunting.