What is a Buy as opposed to a Sell? What defines a Buy vs a Sell record in the trading time series of an exchange? In any trade there is always someone selling and someone buying... So what defines a particular trade as Buy or Sell?
It is from the perspective of the other person (not yours).

When you see Sell, or Sell Orders or Selling or Asks is people willing to sell to you. Thus you look at these entries if you are buying.

When you see Buy, or Buy Orders or Buying or Bids is people willing to buy from you. Thus you look at these entries if you are selling.