Tools—Back
The back tool allows you to place a bet of a specific size at a specific price at an exact time. For example, we can set it to back £50 @ (any price) and then set the hours, minutes and seconds before OR after the start of the event. You can see in this screenshot we have Evo set to back a horse called Spin Again for £50 at 3.00 exactly 10 seconds before the scheduled start time. If the price is above 3.00 when the bet is submitted you will get the best available price above 3.00. If the price is below three then the bet will sit unmatched and when the market suspends it will cancel. If you just want the best available price at the time of submission then put the back price as 1.01 and you will be certain to be matched at the best available price.

You will notice in the picture the button with the – is selected. That means BEFORE the start of the event and + means AFTER. Hover the mouse over these buttons for confirmation. When the + is selected EVO waits until the market goes in play until it submits the bet.
If you select Fill/Kill then the bet will cancel after a time set by you (see Fill or Kill tool).
If you select stop loss then once the bet is placed it will also place a stop loss set by you in the stop loss tool.
If you select Tick Offset, then once the bet activates, and is matched, it will place a tick offset according to your tick offset tool settings.