I check the bookings to get a general idea of what activities to plan.

我核查预订情况以便对计划安排些什么活动有个大体的想法。

We've got a general idea of what we want, but nothing concrete at the moment.

我们对自己想要什么有一个大致的想法，但目前还没有具体的内容。

I have only a general idea.

我只知道个大略。

I have a general idea of what I am going to do.

该怎么做，心里已有大谱儿了。

OK, so that's the general idea.

好滴，这就是大体上的思路了。