Welcome to YT!
As everyone has already said, don't stress about the accidents. Considering you just got him, you're really lucky if he's using the potty pads at all this quickly. He'll get it but yorkies are one of the hardest breeds to house train.
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"If you have men who will exclude any of God’s creatures from the shelter of compassion and pity, you will have men who will deal likewise with their fellow men." — St. Francis of Assisi, 1181-1226