F2L is the second step in the CFOP speedsolving method.
Solving the first two layers together is generally done intuitively by paring a first layer corner with its matching second layer edge. Then inserting the pair into the correct "F2L Slot". Algorithms to pair and insert depends on which F2L Slots are empty. This page will give you some guidance to pair and insert into the front righthand slot without disturbing any other slots.