To add filters to your clip:
Open your clip in the editor by clicking the edit button.
Click on any segment on the timeline that you want to apply a filter to.
When you select a segment, a video panel will open on the right side of the editor.
Below the video preview on the right side panel, click the Style button available on the right side of settings button.
In the style, choose a filter preset to apply that filter to the selected segment.
If you want to add the same filter to the entire clip, repeat the process for each segment by clicking them one by one and applying the filter.
Preview your clip to ensure the filters are applied as you want.
When satisfied, click export.
For a step-by-step visual guide, see the attached video.