Two percent of 5000 is $100.
So this means you do not want to risk more than $100 on your trade.
To use an example 1 mini lot in the EURUSD has 1 pip valued at $1.
The lot size in mini lot trading is 10,000 units of currency.
You need to use a pip calculator if you are going to use pairs other than EURUSD.
since you can only risk $100 on your trade you could trade 1 mini lot and set your stop loss up to 100 pips away.
Or you could trade 2 mini lots and set your stop loss 50 pips away.
If you are an intraday trader looking for multiple entries and exits maybe you want to do 2 trades of 1 mini lot each making your stop loss 50 pips away on each trade.
it`s up to your strategy where you want to set your stop loss and how many lots you want to trade.
Your first goal is to work out 2% in dollar terms then rationalize that on a forex chart so you understand how much movement is equal to how many dollars.
It`s not uncommon for currency pairs to move more than 100 pips a day so one bad trade could mean you are out.
A couple bad weeks in a row and your account won`t look so hot.
Some people like to employ a trailing stop or apply targets to take profits.
Personally I use a moving average trend following system that takes me out on a moving average crossover.
To each his own.