How do I use the Creation Kit to give Aela the Huntress a Deadric Bow and 299 Daedric Arrows in the game???, and, Aela the Huntress is "already" married to my character in Skyrim, please help.

Go to her inventory and add the items you want her to have

You are refering to the Creation Kit right???

Yep

Double click her in the object window, then select the inventory tab.

... and add the objects you want her to have by dragging them into her inventory. It's that simple.

Alright and how do I save my changes in the creation kit correctly???

1. Open the CK. Do NOT load any Data Files
2. SAVE and give your mod a name (and so a file is created ... modname.esp)
3. (I always exit the CK at this stage and restart it, just to be sure)
4. Open the CK
6. Click Data and select your esp then - while it is selected - click the Make Active File Button, which will also select it (this means all changes you make will be saved to your mod file)
7. Double click the tick box next to the skyrim data file (which has all of the bits in it)

To check you are editing/saving to the right file, look at the very top left bar in the CK. It should read: Creation Kit [YourMod.esp]

Simply quit the CK. It will ask you if you want to save your changes, click on "yes", give a name to your esp and that's it. The CK will automatically install it in your data folder.

When I click on "yes" to save my changes in the Creation Kit, I can just name the new file as "Aela the Huntress Edited.esp" right???,... and how do I correctly locate and find the Daedric Bow and the Daedric Arrows to give to Aela the Huntress in the Creation Kit itself???, please help.

Honestly, I would do a save before you ever start modding .... It's the most safe option.

But yes you can do it the way you say (don't use spaces, though)

As for finding the equipment.

Click on "Items" in the Object Window and type in the filter box at the top a few letters ("Daed" for example) - That will show you all weapons with "Daed" in the name/ID. Just pick the one you want and drag to the Inventory Box