If you are new to investing in XEN, it is important to understand the risks and rewards associated with it before you make a purchase. You should research the company, its financials, and its performance in the market before investing. Additionally, you should understand the different types of orders available and the fees associated with each type of order. When you are ready to buy, you can place a limit order to buy 100XEN at a specific price. This will ensure that you get the best price and reduce your risk. If you have any further questions, you should consult a financial advisor or broker to ensure that you are making the right decision.