Click the Find Next Clip button on the AceText Tower to find the first clip after the current one in the active collection containing the search term. AceText starts with the clip below the active one in the clip tree, going down until a match is found. All clips after the current one in the collection will be searched, regardless of the state of the "all clips in this collection" search option.
If the "loop automatically" option is on, and there's no matching clip after the current one, AceText continues searching the first clip in the collection, all the way back down to the current one.
If the "all clips in all collections" search option is on, then AceText searches the next collection if there's no matching clip after the current one in the current collection. The next collection is the one under the tab immediately to the right of the current collection's tab. AceText starts at the topmost clip in the next collection, proceeding downwards until a matching clip is found. If not, AceText will continue searching through the collections from left to right until a match is found. If none is found, and "loop automatically is on", AceText starts searching the first collection (leftmost tab), again proceeding from left to right until a match is found or all collections have been searched.