Hi friends.
I am new to trading and I opened a demo account with ICMarkets.
My demo account is 1000USD with 100:1 leverage.
I bought EURUSD with 0.01(decimal thing).
Now my questions are:
You bought with 0.01 standard lot (100,000 * 0.01 = 1,000 units).
Your margin is the fixed value when you trade. With 100:1 leverage, you need 100 times less to open a lot. Your margin is 11.22 USD ( 1.12175*1000/100).
How do you calculate this one then?
Sorry if I am asking silly questions. I still can’t wrap the basics
Maybe it will be easier this way - each currency pair contains of 2 currencies. Margin is calculated on the basis on the 1st currency in the pair and pip cost is calculated on the basis on the 2nd.
For example, let’s take EURUSD/ In this case you buy/sell EUR. 0.01 = 1000 EUR. Your leverage is 1:100. 1000/100 = 10 EUR is required as margin. And your account currency is USD. So, 10 eur = 11.22 usd (converted by the system automatically).
Now let’s look into USDJPY. Here you buy/sell USD. So, 0.01 = 1000/100 = 10 USD required as margin.
Important Note: Margin is not smth. you’re risking with. This is just the balance requirement you must have to open this trade size. Your risk is determined by the trade size and Stop Loss level (highly recommended). For example, in EURUSD 0.01 lot size, 1 pip costs 10 dollar cents. So, if you bought it at the prices 1.1217 (pip is the 4th digit after a dot), if the prices goes up 10 pips to 1.1227 it will turn into +1 usd and if the price goes down 10 pips to 1.1207 your trade will be -1 usd. So, when you open a trade, you need to decide how much you want to make on it (better to place Take Profit) and how much you are ready to risk (better to place Stop Loss).
Its more clear to me now. Thank you very much 
