Placing a trade on dukascopy europe jforex platform/ risk management/ lot size

Hi, Im new to forex trading and this site, (amazing by the way), however Im having difficulty grasping the lot sizes and risk management Ive watched a load of youtube videos on calculating lot size with 1% risk however on my Dukascopy jforex demo platform when I tried to practice placing a trade on long EUR/USD it only had an option for how many units I wanted to buy, and with the live chat they said because EUR/USD exposure is calculated in EUR and GBP/CHF exposure is calculated in GBP it will be very difficult to risk 1% since base currency is in USD.- this makes no sense, is lot size also measured in units? if somebody could explain step by step how to place a trade with 1% risk on Dukascopy or even skype me and talk me through it like a 5 year old that would be awesome. its probably very simple im just not getting it and I traded options for years, thanks, Dave