which meant BID or OFFER

Note the example of currency Eur / USD follows: 1.1810/1.1813, 1.1810 and 1.1813 is the bid price is the price offer. Bid means the price at which brokers (wholesalers) want to buy our currency. Offer means the price at which brokers (wholesalers) want to sell the currency to us. So if you put buy position, then when the order is executed buy used is the offer price. Meanwhile, when put sell position, then when executed sell order that is used is the bid price
How do I get a profit in trading?
His way is by analyzing a currency pair which will naek or down, and take its difference from the trade.
If you believe the currency will strengthen (naek) immediately do buy position, then wait for prices naek, do closed (sell) when the currency exceeds the purchase price you earlier.
If you believe the currency will weaken (go down) do sell position, wait for prices to fall, do closed (buy) when the currency below the price you'd
As the example is this:
Opening of Euro 1.1750 / 1.1753, you analyze that the euro will be a position naek 1.1770/1.1767, then the open buy position when the price is (then you buy at the position of 1.1753), and when the position changed to 1.1770/1.1773, do the closed position / sell currency these (at position 1.1770)

Consider the example above, the offer price and bid price, notice the difference in price and sellnya buy, and when you use the offer price and when to use the bid price

calculate How can we profit?
We suppose that the level of forex platform that we use is 1:100, then I calculate the profit is
Profit = Margin x (difference between buy-sell price / 100)

for example the difference between purchase price and you sell when the transaction is 70 pips, and used margin (deposit) is $ 10 (for purchase of $ 1000) then
Profit = $ 10 x (70/100) = $ 7

What is market price, stop orders and limit price?
When you open a position of course you will find the option to buy / sell limit price or market price. Market Price is the buy / sell at a price at that time in the market. Stop orders are buy / sell when the market direction as you want, this permisalan price of USD / JPY at 108.72 and you feel it will move higher, you get put a stop order to buy at 108.82, if the price was not up to 108.82 then the order you will not be executed.

While Price is the limit you set yourself when you want to buy / sell at what price level, or by word laen if the current rate you requested is not touched, then the price will not be executed and can be canceled at any time

What is stop loss and take profit?
Stop loss is the lowest price limit or a loss you can bear
Take profit is the highest price restrictions or benefits that may want
if your order is subjected to any one of the constraints that the position will be closed automatically