Newbie question

Just to be clear:

Premiere Elements doesn't store the videos you place in the project.  The files listed in the project act as a shortcut to the actual files.

Your file is offline.

When making movies you have to transfer the files to your computer first then import them into Elements.

If you import them off a external drive and after done editing remove the external drive the files will get offline.

https://helpx.adobe.com/premiere-elements/using/offline-files.html

That means the program can't find the video files in your project

1 - you moved the files to a different folder

2 - you have the files on an external drive and you unplugged the drive

Since you are new...

MANY video tutorials on You Tube
Some are for older versions, but the basic information SHOULD be the same
Look on the left side for some free tutorials https://muvipix.com/pe2022.php
https://community.adobe.com/t5/photoshop-elements-discussions/elements-2022-demo-videos/td-p/12436594
https://youtu.be/fVgrYmoLROk Clearing stray frames from the end of a timeline (orphans)
https://www.youtube.com/watch?v=hjW4UGBZCCI Chroma Key
https://www.youtube.com/watch?v=z-2_qg-zw_k NEW project settings available in version 2022
https://www.youtube.com/watch?v=NG18DktkToI FREE part 1 of 8 for version 2020
https://www.youtube.com/watch?v=j7NCbZUsLqw 2 add media
https://www.youtube.com/watch?v=t7iD-6o6ep4 3 timeline & trimming & auto ripple (alt key to override)
https://www.youtube.com/watch?v=UcaOzJ_7V2s 4 transitions (square box on right with diagonal slice)
https://www.youtube.com/watch?v=XGPtobG8sXQ 5 effects (fx on right)
https://www.youtube.com/watch?v=iAC0Olt3DZA 6 key framing (adjust over time)
https://www.youtube.com/watch?v=6i5SfYvKq0s 7 titles (not show how to insert before/after a clip)
https://www.youtube.com/watch?v=E86tB38yg_w 8 share
https://www.youtube.com/watch?v=T-v4ojCVSBI Using ImgBurn to write a DVD/BluRay
https://www.youtube.com/watch?v=0Ii35Z46-uM PrE 2021 and GPU Accelerated effects
https://www.youtube.com/watch?v=ytMBaatenW0 output only a segment to a file
https://www.youtube.com/watch?v=s-DDRqM4Jbc output part of a timeline to a file
https://www.youtube.com/watch?v=iICFh4ajiXQ recording narration
https://www.youtube.com/watch?v=xlvxgVREX-Y Handbrake file converter
https://www.youtube.com/watch?v=hUPpc7RUAJ8 add a moving line to a map
https://www.youtube.com/watch?v=fVgrYmoLROk clear stray frames on the timeline
https://www.youtube.com/watch?v=4eyx0tkzkuc change project settings
https://www.youtube.com/watch?v=E3Rech6P0-0 movie menu markers v13
https://www.youtube.com/watch?v=KpGGtH5xvzk customize movie menus v13
https://www.youtube.com/watch?v=PHh2D_CDmeI time lapse guided edit
https://www.youtube.com/watch?v=5u16h83rHIQ L cuts and J cuts
https://www.youtube.com/watch?v=uWM89KZ-yDI introductions
https://www.youtube.com/watch?v=aOPZvWLKtHc tips 1-5 version 13
https://www.youtube.com/watch?v=pYd9iC1QiZ8 tips 6-10 version 13
https://www.youtube.com/watch?v=KPg0J5HXLRk tips 11-15 version 13
https://www.youtube.com/watch?v=-smBkLHZmWc zoom transitions
https://www.youtube.com/watch?v=QO1gWfL6bNM spotlight a person in motion
https://www.youtube.com/watch?v=cIWAvZsx3qo clone yourself
https://www.youtube.com/watch?v=_4xFwiUAaMY V2020 tutorial for beginners
https://www.youtube.com/watch?v=rCItXu6A45E adding text
https://www.youtube.com/watch?v=QDm5QNR240o titles v18
https://www.youtube.com/watch?v=PBNsNF-nrX8 transitions
https://www.youtube.com/watch?v=X265_ZAbaxk slideshow
https://www.youtube.com/watch?v=k1sKZArLONA slide show shortcuts
https://www.youtube.com/watch?v=ziOqbR1Cuy0 music remix v15
https://www.youtube.com/watch?v=xJ_lI90AY00 video collage v15
https://www.youtube.com/watch?v=hjW4UGBZCCI chroma key & videomerge v15
https://www.youtube.com/watch?v=5VIO2aFeGHs 5 PIP effects
https://www.youtube.com/watch?v=JCQn-xAyo-U blur a face v15
https://www.youtube.com/watch?v=zw6opX9E_iU slow motion & fast motion
https://www.youtube.com/watch?v=M5l71denvp0 noise/grain removal tool
https://www.youtube.com/watch?v=0ayCyQ7GZWs how to edit a video
https://www.youtube.com/watch?v=w-i5RQxttx4 another tutorial part 1
https://www.youtube.com/watch?v=lXG1xcbOxLc tutorial for beginners
https://www.youtube.com/watch?v=z-2_qg-zw_k How to make a vertical video V-2022
https://www.youtube.com/watch?v=E2kLOnOnx9c Sync audio using Audacity