Sacred Tradition (abbreviated ST) is Apostolical Doctrine which was not necessarily written down or codified in the Sacred Scriptures. Examples of Sacred Apostolic Traditions are the Perpetual Virginity of Mary, purgatory, indulgences, the Pope and his Supremacy, the Dormition of Mary, the Immaculate Conception of Mary, the intercession of Mary and the Saints in Heaven, prayers for the dead, and many others. These are all either explicitly or at least implicitly rooted in Sacred Scripture, and in fact the canon of Sacred Scripture itself is a Sacred Tradition. Sacred Tradition and Sacred Scripture are inseparable - the two make up together the Deposit of Faith, which is disseminated to the People of God by the Magisterium of the Church (Her infallible teaching Authority).
Catholic traditions (small t traditions - abbreviated here as Ct) are things like the way we cross ourselves (Roman vs Eastern style, which are both legitimate Catholic forms), the use of leavened vs unleavened bread in the Eucharist, devotions like the Rosary or the Jesus Prayer, mandatory priestly celibacy in the Roman Rite vs a married priesthood in the Eastern Rites, etc.
Some Catholic things fall under both ST and Ct - for example, the praying of the Liturgy of the Hours and the Holy Sacrifice of the Mass are both in there substance ST, but in there various forms (Extraordinary or Tridentine vs Ordinary or Pauline, Byzantine vs Roman, etc) are Ct.
ST’s are for the most part immutable matters of dogma and doctrine. Ct on the other hand are usually related to either disciplinary practices, devotional practices, or cultural phenomena and are subject to change, updates in form, new things being added or assimilated, etc. ST is best embodied by the Sacraments; Ct is best embodied by sacramentals.