There are five distinct sets of climate data that comprise the projections. These are described in more detail covering what has been generated, how it has been done and how it might be useful to your applications.
It is not possible to give a precise prediction of how weather and climate will change years into the future so UKCP18 provides ranges that aim to capture a spread of climate response based on our current knowledge. You can explore the types and magnitudes of climate change that are projected for the future. Depending on the purpose and the level of your risk aversion, you may choose to focus on the full range of outcomes or pay particular attention to parts of the distribution such as the largest projected changes.
See how the projections over land are connected to each other in this schematic [167KB] and also UKCP18 Guidance: How to use the land projections [1.8MB]. You may also find this schematic [52KB] helpful to understand which sets of information to use.