Enter Insert mode after the cursor with a or at the end of the line with A. These are fast append commands for continuing existing text.
Commands you practise
a
Press a to start typing immediately after the cursor. It is the fastest way to append a character to the current word without moving first.
A
A jumps to the end of the current line and enters Insert mode. It is the fastest way to append text or fix missing punctuation.
Levels
Fruit Appender (easy): Append the missing last letter to each fruit name using the append command.
Semicolon Slinger (medium): Quickly append missing semicolons to the end of each variable declaration.
Code Polisher (hard): Fix the syntax errors by inserting characters both inside and at the end of the lines.
Each level opens a real Neovim session in your browser with a start file and a target file. Edit one into the other in as few keystrokes as you can, then race the vimbot's solution.