In this part of the documentation you will find information telling you how to build OP-TEE as a whole developer setup or as individual components. Likewise it will also tell you how to run OP-TEE on various devices.
Since you pressed this, it's likely that you want to know how to build a full OP-TEE developer setup. So a first place to start looking is probably at the "build" page to get started.
aosp/aosp devices/index linux/tee_framework gits/index prerequisites toolchains trusted_applications