The APY that is displayed for each farming pool represents the combination of ALL the different yields you would get. This includes returns from PICKLE rewards, Pickle Jar returns, Uniswap or Sushiswap LP fees, etc. Hovering over the APY number will show you the breakdown.
Simply put, a Farm weight translates into how much of the PICKLE emissions a particular Farm receives. Each week, every farm is allocated a percentage of the total emissions. The below image illustrates an example distribution of weights.
Farm weights are updated weekly on Thursdays at midnight UTC. The most recent votes of eligible governance members will take effect at that time every week.
Users who have locked their PICKLEs for DILL will be able to vote on how they would like their vote weight to be distributed across one or more Farms. The weights ultimately applied to the various Farms depend on the allocation and DILL balance of the users who vote. In short, users with more DILL get more voting power. Users can cast their votes on the farms page. A guide on how to do so can be found here.