How do you get the numbers in the top left of your screen? They show as followed name: pos: ang: vel: vel:

I'm trying to figure out how trading works in the record by dream to try this speedrun myself (https://www.youtube.com/watch?time_continue=989&v=fj28UtF0-Fs&feature=emb_title), but whenever I try to recreate what dream did the villager brings his stick price up to 57 per emerald after his first restock. I also don't see how at 16:25 of the video, dream continues to trade sticks for emeralds after the villager ran out of stock.

Am I allowed to pause the game the second the world is generated to change the world difficulty to easy without it adding time to my run?