Hi Tywa, and welcome to the forum!
Adding things to M&P is super easy. After you have melted your M&P in the microwave, add your scent and color while it is still liquid and hot. Unlike CP soap, you don't have to worry about trace, so just drop it in and go. Make sure to follow the directions for your color and scent. I usually don't put anymore than .25 of an ounce in a 1 lb of soap. Some people like more but I have found that many fragrances are rather strong.
After you have mixed everything by hand with a spatula, just put the soap in your desired mold and let it set. Depending on your mold, this can take anywhere from an hour to six. I prefer using high quality silicone molds since it is super easy to get it out of the mold and there are many beautiful molds created by Wilson on the market. If this is your fast batch, its best to keep it simple while you are learning.
Hope I helped