Shemmy, knowing Lama Rinchen primarily practices the Dudjom Tersar I am confident that the practice you did was the Khandro Thugtik tsok sadhana, which is the general tsok practice performed on the 25th day of the lunar calendar every month by practitioners in this lineage. This is a very profound practice with many levels of meaning, and to really do it properly it is important to have a good understanding of what is going on, the details of the visualizations, the correct way to handle the offering substances, etc. In other words, you really need detailed teachings-- and even after that it would be best to practice it regularly with experienced practitioners if not a Lama to watch how they do it and to make deeper contact with the energy of the practice when it is done correctly.
This might seem difficult, even impossible where you are-- however if you look at the history of Vajrayana, many of the great adepts did not have an easy time accessing the teachings or dealing with their Gurus -- there is a price for things this precious, even if it is simply our own extraordinary effort.
If you deeply feel moved to develop a cohesive knowledge of this practice, so that you can perform it at home or with other locals, then what I recommend is that you make a formal request of either Lama Rinchen or another Dudjom lineage Lama to come back to your area and turn the wheel of Dharma-- to give detailed instructions on the practice of Tsok-- it's meaning, the visualizations, how to perform it, etc. If you can arrange for it, request both for the Dakini tsok (Khandro Thuktig) and the Guru Rinpoche tsok performed on the 10th day of the lunar calendar (Lakeborn Guru Rinpoche / Guru Tsokye Tugtik) . The way to make a formal request would be very politely with a "mandala offering" --which can simply be a generous amount of money that you collect among the people interested in receiving these teachings. This offering creates an auspicious inter-dependence and plants good seeds for the request to bear fruit. You could also offer to cover airfare, a place to stay, etc.
In the meantime, diligently continuing the ngondro will deepen your natural connection to all these practices. If you are able to secure the TNR "Cascading Waterfall of Nectar" text that we discussed then at the end, --after the ngondro commentary there is an entire section written about the practice of tsok, and specifically a very concise tsok offering prayer that is generally recited along with the Khandro Thugtik practice.