No, expiration time is not linked with candles, it's N minutes after the creation of the trade. Technically, in the Comment of the trade some information is written and then the EA reads this information and decides when to close that trade. This is for trades. For pending orders, their expiration works on the server.
I think I don't understand your candles. I decided that you want to open trades at certain pips away from the first trade and with different lot sizes. But if this is something like renko... maybe just use renko.
Candle Time. So, go to your History Center and you will see that each candle has O, H, L, C, Volume and... Time. This is the rounded time at which the candle is positioned. For H1 we have candles at 00:00, 01:00, 02:00 and so on.
As a variable, the Time is an integer value, a whole number value. Also known as Epoch or Unix Timestamp. The number of seconds since 01.01.1970. Here is more - http://www.epochconverter.com/