It's simple. You can choose to buy it once or in batches. If you choose to buy once and want to buy again in the future, you can operate according to your personal financial situation. Remember to buy it with long money that has not been used for more than 3 years.

About how to sell:

The funds selected by the portfolio can be redeemed normally every day. The reason why it is repeatedly emphasized that "idle money" that has been useless for more than three years should be used to follow the investment is because in order to achieve medium and high returns, a certain proportion of flexible varieties, such as stock base, need to be added to the portfolio, which is easy to lose money because of its short holding period. So, when you need money, you can sell it. However, in order to make the real income of your account as close as possible to expectations, it is best to hold it for more than 3 years. Of course, after three years, you can keep more money.