按图索骥的英文：
try to locate sth by following up a clue
[Literal Meaning]
according to/picture/look for/an able steed.
to look for a good horse with the aid of its picture
[解释]
根据现有的规定办事；也比喻根据线索去寻找。
[Explanation]
to stick to old conventions; to look for something according to information at one's disposal
[例子]
在处理外交事务时我们不能按图索骥，需要高度的灵活性。
[Example]
When dealing with diplomatic affairs, we should not stick to old conventions, but need great flexibility.
- Look for a steed with the aid of its picture;try to locate sth. by following up a clue
按图索骥 - Locate something by a plan or chart
按图索骥