A CW contact follows a standard pattern, so strangers who share no language can still complete one. To start, listen first, then ask QRL? ("is this frequency in use?") before you call. If it is clear, send a CQ.
A typical HF CQ. N0CALL is a placeholder: use your own call sign.
Answer by sending their call sign once or twice, DE, and your call sign. Answer at or below the speed of the CQ, and tune your transmitter to the frequency you hear them on, so they are not hunting for you. Then wait for them to come back.
Prosigns
A prosign is a procedural signal. Most are two letters sent run together as one character, with no gap between them, and are written with a bar over the letters or just as the pair. A few procedural signals, like K, are a single letter.
Prosign = letters sent run together as one character.
Signal
Means
K
over: go ahead
KN
go ahead, only the station I named
AR
end of message
AS
wait
BK
break: quick hand-over between stations
BT
pause, a separator between parts of a message; often written =
SK
end of contact
A typical QSO
Illustrative. Real QSOs vary, and operators shorten or skip parts. N0CALL and N0DEMO are placeholders.
A first exchange is usually the RST report, a name and a location. In RST, the numbers give Readability (1 to 5), Strength (1 to 9) and Tone (1 to 9), so 599 is perfect. A trailing C flags a chirpy signal, a tone that shifts as it is keyed.
Match speed. Send no faster than the other operator can copy. QRS is a polite request to slow down.
Don't send faster than you can copy. A fast CQ invites replies you may not understand.
Full break-in (QSK) lets you hear the other station between your own elements, so they can interrupt in the middle of your transmission. Without it, you need to flip to receive.
Send your call sign clearly, and repeat it when the band is noisy.