Once you have reached the stage where all the colour is trowelled in, time should be available, prior to printing, to clean off equipment and surrounding areas. In normal conditions and having used the correct equipment, you should have reached this stage before the concrete has set. It takes experience to handle large areas even with plenty help, beginners should never exceed loads of 3m3.
Concrete release agents acts as a barrier between the colour and the imprinting mats to stop the mats from sticking to the concrete, it is also coloured to add a further dimension to the look, like an antiquing affect to resemble aged stone. It is also a curing agent which traps moisture in to slow down the setting rate.
Spread a small amount of release agent where you are going to start and place your first mat in position, this should be able to take your weight without distortion, you should feel some give into the concrete. If the concrete is too soft the mat will unduly distort under your weight – a good test prior to laying your first mat is to push your finger into the concrete, should you get little resistance then the concrete is too soft, should you find you are only able to depress the your finger into the surface, then you should be ready to print.