Health Education England operates a national recruitment scheme for all hospital placements and many of the other training providers in England through their online application portal: Oriel. If you want to start your training directly after you finish your MPharm or OSPAP, you will need to apply to the scheme in June of the year before the one when you will finish. If you are studying an OSPAP course, this could be before your course begins.
In Scotland the Foundation Training Year is managed by NHS Education for Scotland. They operate the national recruitment scheme for all FTY training posts in Scotland via the Oriel online application portal.