I have a website someone designed for me in AI but i am not sure how to crop out pieces and select layers and save them to design my website. I am only used to the way of photoshop finding the layer and cropping it and saving it. How do i crop out images and select them on AI and save them? Also how do i save transparent images?
You don't have to crop. In both Adobe Illustrator and Photoshop you can use a technique called slicing to extract web graphics from the artboard. I'll post some links so that you can get started with slicing in Illustrator. After you have sliced your webpage into the elements you want, use
Here are some links to help learn slicing in Illustrator:
When you export your slices in Illustrator via Save for Web & Devices, you will see an option at the top right of the save window that allows you to select the export file type. One of the options there is PNG. This will create a PNG image with transparency wherever the white artboard background is showing in your slice. If any unwanted graphic is blocking the artboard background, you must hide it by locating it in the Layers panel and clicking on its Visibility (eye) icon.
Regarding layers in Illustrator... There could be many shapes in a single layer. If you are trying to hide part of the design temporarily, you may need to expand the layer by clicking on the little arrow to the left of its name in the Layers panel and then look for the shape icon/name that matches the one you want to hide.