Excuse me, what does "copy first, then draw red" mean in practicing pen copybook? Thanks in advance!

Copying is to paste a piece of white paper like most pen copybooks on the market now, put the white paper on the sticker and write according to the words below the paper. Pro means to refer to the copybook, put the paper next to the copybook and write like a copybook. Draw red, that is, draw glyphs around each radical of a word according to the stroke order. Drawing red is beneficial to mastering glyphs.