Remember, you can check the full document Paschale Solemnitatis on this site, among many on the internet.
What not to do on Holy Saturday? No celebration of Mass is obvious. No Communion to the Sick:
75. On this day the Church abstains strictly from the celebration of the Sacrifice of the Mass. (Roman Missal) Holy Communion may be given only in the form of Viaticum. The celebration of marriages is forbidden, as also the celebration of other sacraments, except those of Penance and the Anointing of the Sick.
Communion for the dying, and the two healing sacraments are fine. It’s not mentioned here, but I’d say baptism is out, too.
76. The faithful are to be instructed on the special character of Holy Saturday. (SRC, Decr. Maxima redemptionis nostrae mysteria (16 Nov. 1955), n. 2, AAS 47 (1955), 843) Festive customs and traditions associated with this day on account of the former practice of anticipating the celebration of Easter on Holy Saturday should be reserved for Easter night and the day that follows.
Another thing not to do is any sort of Easter blessing. No eggs, food, bread, or such.