New to Sous Vude. Can I put Multiple bags in at the same time?
Yes, as long as the water is free to cirulate around each bag.
If you are doing something like steaks for different people who may like them medium, but you want yours rare, then you can do the medium one first then reduce the temperature and leave that bag in when you add another bag wiith the steaks that you want to do as rare as they will not over cook the medium one or dry it out. Once your rare steak is done you can take all of them out and sear then serve them.
Welcome @DrFerry912
Yes, one can use multiple bags. Some recipes call for a bag per piece, like the pork chops that I just did for dinner.
Racks are usually arranged for a number of bags of pieces.
I just clothespin the bags to the edge of the tub.
Hi DrFerry.
Office “bulldog clips” can be a useful clip to steady bags around the water vessels edge (for some items) to help maintain a good circulation, cheap, durable, often able to pin foodbags down further with wide spoons clipped in place (you know your cutlery draw better than I) 
What size container are you using? …for instance I often use an 8 litre capacity s/steel instantpot inner which if overcrowding the circulation flow will produce different results for the same steaks sunk at the same time due to interrupted thermal flow
But I also have an insulated ice box, of much larger capacity, shape & the eddying flow therefore are different (can be handy to sink a s/steel rib rack holder for bags, tidy, consistent spacing & therefore eddying flow)
Container size, shape, how full of items you pile it, & the specified capacity of your individual sous vide stick are going to make a difference, start small (an excuse to eat) & get your confidence with texture, finishing, & cooking capacity before you go wild.
(& if you have a dog, you will be harassed for cooking bag food juices, “they know” )