旟 is a traditional Chinese hanzi, listed here under the keyword “an military flag or standard”. It is built from 方 (a square), 𠂉 (reclining) and 與 (and).
On KumiJi Glyph Explorer, open the parts search and type “a square” + “reclining” + “and”. 旟 is among the results, together with every other character containing the same shapes.
Open 旟 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.