In Scid, you can enter the moves for a game using the mouse or the keyboard. As you move the mouse over a square, it and one other square will change color if there is a legal move to or from that square. This is the suggested move. To make this move simply click the left mouse button. You can turn off move suggestion using the Options menu if it annoys you.
To make any move other than the suggested move, you can use the left mouse button: just press the button over one square, and release it over the other square.
If you prefer to make moves with two mouse clicks instead of dragging with the mouse button pressed, you can use the middle button: just click on one square then the other.
To take back a move, click the right mouse button. This goes back one move, and deletes the move if it is the last in the game or variation.
When you enter a move at a point in the game where a move already exists, Scid will present a dialog box asking if you really want to replace the old move (the old move and all moves after it will be lost), or want to add the new move as a variation instead. Some people may find this dialog box annoying and always want to replace old moves, so it can be turned off with the [Options: Moves] menu option "Ask before replacing moves".
If you are studying a game and reach a position where you want to try an alternative variation on the board without altering the game, select Try variation from the [Edit] menu to enter trial mode. In this mode, you can make temporary moves and changes to the game, then return to the original position when you exit trial mode.
If you are entering a game and suddenly see an incorrect move several moves earlier, it is possible to correct it without losing the extra moves you have added. The only way is to edit the PGN representation of the game: open the Import window, select "Paste current game", correct the incorrect move, then select "Import".
To enter moves at the keyboard, simply press letter and digit keys. Note that accepted moves should be in SAN notation, without the capture symbol (x) or the promotion symbol (=). Moves are matched case-insensitively, so you can type [n][f][3] instead of Nf3, for example -- but see the note below about conflicts with pawn moves.
To ensure that no move is a prefix of any other move, the notation for kingside and queenside castling is [O][K] and [O][Q] respectively, instead of the usual O-O and O-O-O.
As you enter a move, the status bar will show the list of matching moves. You can press the [space] bar at any time to choose the first matching move in the list and add it to the game. To delete a character, press [Backspace] or [Delete].
Note that a lower-case letter matches to a pawn first, so a [b] can match to a pawn or Bishop, but if there is a conflict you must use a capital [B] for the Bishop move.
In the Options menu, you can turn on or off Auto-Completion of moves. With auto-completion, a move is made as soon as you have typed enough to distinguish it from any other legal move. For example, with auto-completion, you would only need to type [n][f] instead of [n][f][3] for Nf3 in the starting position.
Null (empty) moves can be useful in variations, where you want to skip a move for one side. You can enter a null move with the mouse by capturing one king with the other king, or with the keyboard by typing "--" (that is, pressing the minus key twice).
You can also add common annotation symbols using the keyboard in the main window, without needing to use the comment editor window. The following list shows which symbols you can add, and their keyboard shortcuts: