Here scribe 2 of 𝓟 appears to have accidentally missed the and after “go forth”. Oliver Cowdery inserted an ampersand, probably based on the reading of the original manuscript. Elsewhere in the text, we always get an and after an imperative “go forth” and before a following imperative:
Thus Oliver’s correction is consistent with usage elsewhere in the text.
Summary: Maintain in Alma 8:29 the and after “go forth”, Oliver Cowdery’s corrected reading in 𝓟; this reading is consistent with all other instances of this imperative construction in the text (as “go forth and ”).