I need instructions on removing links from a Fossil Stella watch

You will need some sort of tool for a pin pusher to actually remove the pin from watch . It can be a strong needle of some sorts but I suggest getting an actual pin pusher to prevent from damaging the watch or hurting yourself.

if you look inside the watch band itself you will see on the links an arrow pointing one direction. That is the direction you need to push the pin since the pin head is larger and cannot be pushed the opposite direction .

On the side of the watch links you will see a small circle endented with a pin head. That is the link pin. Place your pin pusher or other similar sized object and with a small or jeweler hammer slowly and lightly hit the pin pusher down until pin comes out of opposite side , you can use tweezers or needle nose pliers to pull pin all the way out

There are some pin removers that screw also or just push down to pop pin .

Once out repeat process until you have removed enough links that watch fits comfortably. Then slide pins with head of pin entering the side where the arrow on back of link is pointing to. Once all the way in gently hammer rest of pin till flush with link .