Update README.md

Co-authored-by: Remi <re.cadene@gmail.com>

README.md

@@ -145,7 +145,7 @@ Our script can also visualize datasets stored on a distant server. See `python l
 
 A dataset in `LeRobotDataset` format is very simple to use. It can be loaded from a repository on the Hugging Face hub or a local folder simply with e.g. `dataset = LeRobotDataset("lerobot/aloha_static_coffee")` and can be indexed into like any Hugging Face and Pytorch dataset. For instance `dataset[0]` will retrieve a sample of the dataset observations and actions in pytorch tensors format ready to be fed to a model.
 
-A specificity of `LeRobotDataset` is that we can retrieve several frames for one sample query. By setting `delta_timestamps` to to a list of delta timestamps, e.g. `delta_timestamps = {"observation.image": [-1, -0.5, -0.20, 0]}`  one can retrieve, for each query, 4 images before the current time frame. See example [1_load_lerobot_dataset.py](examples/1_load_lerobot_dataset.py) for more details on `delta_timestamps`.
+A specificity of `LeRobotDataset` is that we can retrieve several frames for one sample query. By setting `delta_timestamps` to a list of delta timestamps, e.g. `delta_timestamps = {"observation.image": [-1, -0.5, -0.2, 0]}`  one can retrieve, for each query, 4 images including one at -1 second before the current time step, the two others at -0.5 second and -0.2, and the final one at the current time step (0 second). See example [1_load_lerobot_dataset.py](examples/1_load_lerobot_dataset.py) for more details on `delta_timestamps`.
 
 Under the hood, the `LeRobotDataset` format makes use of several ways to serialize data which can be useful to understand if you plan to work more closely with this format. We tried to make a flexible yet simple dataset format that would cover most type of features and specificities present in RL and robotics.