Stating the purpose of what we are doing is an important thing to know how to do in any language. Without knowing how to do it, you will have difficulties explaining your intentions or the purpose of a certain action. In Korean, you can use the form -(으)려고 to indicate the purpose of what you are doing.
The form -(으)려고 is similar to the form -(으)러. Both forms indicate the purpose of an action. However, whereas you use -(으)러 to indicate the purpose of going somewhere, with -(으)려고 you can express the purpose of any action. In a certain way, the latter offers a lot more flexibility, though it has its limitations that the former does not suffer from.
가: 새해 후에 운동센터에 자주 가요. 왜요?
나: 살을 빼려고 열심히 운동하기로 했어요.
A: Since New Year, you often go to the gym. Why?
B: I’ve decided to exercise a lot to lose weight.
How To Use
Using the form -(으)려고 is not that difficult at all as long as you keep a few things in mind. The first thing you need to learn is, of course, the conjugation rule. The conjugation follows the ‘batchim/no batchim’ rule. This means you will have to use -으려고 when the verb stem ends in a batchim (consonant). But, you use -려고 when the verb ends in a vowel (no batchim), or when it ends in ㄹ batchim which is treated as if it were no batchim. Of course, you still need to keep minding those Korean irregular verbs.
Besides conjugation rules, there are a few things you cannot do with -(으)려고. While it is possible to use the present tense and the past tense in the second clause, using the future tense, like -(으)ㄹ 거예요, is simply awkward. Furthermore, this form sounds awkward with forms to express suggestions, like -(으)ㄹ래요, or imperatives, like -아/어 주세요. If you want to use to express the purpose of suggestions or imperatives, you can use the form 위해(서) instead.