This summary is drawn from the Rebbe's letters to him (about 5715–5723, 1955–1963); I did not find a published biography.
Taking an active role. The Rebbe urged him not to stand aside from communal projects out of self-doubt, but to take active leadership in the yeshivah project (IK 5365), and to use moments of inspiration, such as a meaningful reunion, to strengthen Torah education (IK 5476). True spiritual growth, he wrote, includes inspiring others and not only personal advancement (IK 5140).
The yeshivah in Kiryat Gat. Several letters concern establishing a branch of the yeshivah in Kiryat Gat: careful planning and the right institutional affiliation (IK 6696, 6729), naming a building after the yeshivah's supporters when they take on its expenses (IK 8117), and blessings for the founders of this holy institution (IK 8474).
Torah study. In an early letter the Rebbe explained the "vitalizing soul" as described in Tanya chapter 1 and gave guidance on Torah study (IK 3490). His New Year letters asked for blessings in both material and spiritual matters (IK 7890).
Sources: the Rebbe's letters cited above.