It's all a learning curve. Have patience.🙂
First, Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar. This for your protection.
To remove a portion of a clip, use splits at the in and out points, then click on the part that you have isolated and press the DEL key. Or right-click on that area and DELETE(Ripple), which should close the gap left by the deletion. If it does not, right-click within the gap and Close Gap.
If you make a mistake immediately press <ctrl-Z> to backtrack, step-by-step. And, of course, you have a recent back up of the Saved Project File.
Moving a clip can cause several actions. If the mouse pointer is placed within the clip to drag right, it may cover other clips. To avoid that, and drag ALL clips to the right, first select (highlight) each by holding down <ctrl> and clicking them, one-by-one. Or click the first clip to select it, then hold down <shift> and click the last. All within the range will be selected. Then drag.
Alternatively, select the desired clips, right-click and GROUP them, so they will all move in concert when any one of them is dragged.
If a clip is typical video and audio linked together, then deleting video will also affect the audio, to keep it in sync. If it UNlinked - perhaps a music track - then audio and video will be independent so deleting portions of one won't affect the other.
Del_Ripple.mp4
For some good tips check out the tutorials.