Looker makes it really easy to filter data. First, hover over the field you're looking to filter, and click the Filter button. For example, if we were interested in filtering by Payment ID in our Payments Explore:
Once you click Filter, Looker will prompt you for your filter logic in the Filters section of the Explore (the accordion at the top).
For instance, here's us pulling User ID and Payment ID from our Payments Explore filtering for User ID is equal to 1:
Filtering by an additional field is done via the same process. For instance, filtering by Payment Amount >= $100 and Payment Returned is FALSE:
And finally, Looker also has the ability to instrument AND, or OR logic via use of the " + " icon. Looker will ultimately determine which option is available to you. Here's an example of a search for payments >= $100 and the payment took place in Q1 2018 or 2019: