I am certainly not as well versed as others on this forum, however, I will attempt to answer your questions as best I can.
The very first icon was made by Christ, Himself. "The Icon Made Without Hands". If you want a history of this, I or others will be happy to provide it.
However, because Christ left us an "image" of Himself, therefore, it is permitted to have icons.
Secondly, since Christ was completely human, not only divine, due to his human nature, man has seen His face and therefore, can reproduce it. On the other hand, God the Father, has not been seen by "man" and therefore, should not be depicted by mankind. Make sense?
As for the use of icons during Liturgy. There is the iconostasis in the church, which is an icon wall separating the Altar area from the Nave. It symbolizes the separation of Heaven and Earth. From the Altar the priest walks out with the Gospel (representing Christ (the Word) coming to Mankind). There is much more symbolism, but, I don't want to confuse you with too much information.
Finally, the iconostasis works as a "picture book". In the olden days people did not know how to read, therefore, the Bible was depicted before them in the icons. They would be able to "read" the entire life of Christ and His Saints.
Remember, when we kiss or venerate icons, we are in actuality transferring our respect and love to the individual depicted on the icon, not the wood and paint, itself. It's like having a photograph of a loved one. When you miss your loved one, you will pick up that photo and plant a kiss on it. You certainly aren't kissing the Kodak paper, you are in fact kissing the loved one.
Welcome to the forum.
God bless you as you make your way in to the Orthodox Church.