Lay practitioners are always welcome to visit the monastery and observe or join the regular Chod and Cham practice sessions, which are normally held each evening. The schedule is somewhat flexible and it is always best to stop by the monastery to learn the schedule for any given week.
As noted elsewhere on this site, Rinpoche rarely gives teachings in Nepal and doesn’t offer formal instruction in Chod or Cham. If you wish to learn or practice, just show up and jump in. One of the monks or another lay practitioner will probably have a copy of the text, called Bellowing Laugh of the Dakini, that you can use if you don’t have one with you. You will often meet other practitioners that speak your native language, especially if you are American, German or Russian (who knows why?) so you can ask questions. Mostly, though, RInpoche encourages practitioners to learn how to practice by practicing and that certainly applies here.
Several times a month, the monastery will offer the Chod practice from RInchen Trengwa. This is an extensive sadhana; from start to finish a practice session can run up to seven hours. Again, there are often English language versions of the text around (with transliterated Tibetan) that will help you follow along. Rinchen Trengwa practice typically takes place on feast days and there will often be a crowd of observers along with a group of lay practitioners, joining the monks.
The evening Chod practice sessions are led by one or more of the senior monks, or one of the junior monks that is training in a particular shrine hall position. Senior monks also lead the opening practice in Rinchen Trengwa and are joined by Rinpoche for the main practice and feast offering when he is in residence.