Select and speed up

I need to select a part of a video and speed up only that part.

I found where to speed up, but I have no found how can I select a part of the video.. how can I do it?
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Hi,
1.Import your video into resource list.
2. Drag the video to timeline from resource list.
3. Double click it .
4. A property panel will be shown, you can adjust the speed value.
The same as for Audio.

Thanks.