How to carry out functions in a sequential manner

Hi
I'm new to Javascript/Espruino and trying to get a 4D Systems oled gmd-128 Display (serial connection) to work.
After each command is sent the display responds with an ack(0x06) if successful and next command should not be sent until ack is received.

I have managed to get the display working by using the setTimeout('func',td);
but this is not the most efficient way.

I would appreciate any info has to how to "force" sequential operation ie
Send command 1
wait for ack
Send command 2
wait for ack
etc

regards
Gerry

ps hope this makes sense !