Log into TUportal, click on the Home tab, and click on the Adobe Creative Cloud link. On that page, you will click to subscribe and answer some short questions about how you will use the software. For more information you can visit the Temple University help page dealing with Creative Cloud.
Aspect ratio describes the relationship between the height and width of a screen, image, or video. Resolution is how many pixels wide and how many pixels tall the image, video, or screen is. Check out this video on the topic. The video includes lots of examples of why each one is important and how they relate.
To resize your image, click on Image...Image Size. In the dialog box that appears, enter your new width or height. As long as the lock icon appears between the two, changing one variable will automatically change the other to keep the same aspect ratio. Watch this video for help on resizing and cropping using Photoshop.
Sites offering decent selections of files classified as Creative Commons that were used in the training videos include Sound Bible, Sound Image, Mixkit, and Freesound.
You can enter your portfolio directly by visiting https://portfolio.adobe.com or you can open TUportal and access Creative Cloud by clicking Home ... Adobe Creative Cloud ... and if registered, you can click the Access Adobe Creative Cloud button and once opened, go to web apps and open Adobe Portfolio.