My most dear, most kind, most precious, wish-fulfilling one,
Thank you for your kind letter. I am sorry for the long delay. Regarding your question, I checked and service at a center is best, then retreat is best. That means sometimes you can do retreat.
You can offer service during the day, then do retreat at night time. Or you can do retreat and when that is finished, then you can offer service, then again do retreat. You can also do like that.
For you, the main lamrim text to use is Lama Tsongkhapa’s Middle Lamrim. If you can, study that five times from beginning to end. Read it mindfully and in that way, it becomes meditation.
Also, the Guhyasamaja root text—if you can, read it every week for your whole life. I don’t know if it is translated into Spanish.
Taking the eight Mahayana precepts is the best one, especially on Buddha days or when there is a lunar eclipse or solar eclipse. In Tibetan the eclipses are called moon-catching and sun-catching. During moon-catching [a lunar eclipse] any merit you collect is multiplied 700,000 times and during sun-catching [a solar eclipse] the merit you collect is multiplied 100 million times.
On Buddha days the merit you collect is multiplied 100 million times, so it is unbelievably powerful. You also collect more merit on other days, like the Tibetan 8th, 15th and 30th, but you can take the eight Mahayana precepts at any other time, when you can.
Attached is the morning motivation, [The Method to Transform a Suffering Life into Happiness (Including Enlightenment).] Please do that and also please follow my general advice on practice.
Please make your life most meaningful with the thought of bodhicitta in every action you do.
With much love and prayers ...